TABLE 4 ESTIMATES OF 13-MONTH SMOOTH SOLAR ACTIVITY FOR BALANCE OF CYCLE 23 CYCLE 24 AND BEGINNING OF CYCLE 25 TIME SUNSPOT NUMBERS GEOMAGNETIC INDEX (Ap) PERCENTILE PERCENTILE 95.0% 50% 5.0% 95.0% 50% 5.0% 1998.7507 OCT 77.4 72.8 70.7 13.6 12.9 12.1 1998.8340 NOV 85.1 75.9 70.4 14.3 13.1 11.6 1998.9173 DEC 91.5 78.8 69.0 14.9 13.3 11.2 1999.0007 JAN 96.6 81.1 70.5 15.8 13.7 11.0 1999.0840 FEB 101.1 83.2 70.5 16.7 14.1 11.2 1999.1673 MAR 107.3 85.5 68.0 16.9 14.3 11.4 1999.2507 APR 115.0 87.7 64.9 17.0 14.6 11.9 1999.3340 MAY 122.4 90.0 60.7 17.1 14.9 12.4 1999.4173 JUN 127.3 92.2 57.2 17.1 15.0 12.8 1999.5007 JUL 130.4 94.2 55.6 17.1 15.0 13.1 1999.5840 AUG 133.6 96.1 55.2 17.6 15.2 13.2 1999.6673 SEP 137.8 98.2 56.1 18.3 15.2 13.0 1999.7507 OCT 141.3 100.0 56.0 19.0 15.1 12.5 1999.8340 NOV 143.1 101.3 54.5 18.9 15.2 12.3 1999.9173 DEC 143.2 102.2 53.0 18.6 15.4 12.4 2000.0007 JAN 142.7 102.3 50.8 18.8 15.6 12.4 2000.0840 FEB 141.7 102.8 50.9 19.6 16.1 12.2 2000.1673 MAR 141.9 103.8 52.7 20.5 16.4 12.1 2000.2507 APR 144.4 104.4 53.4 20.4 16.4 11.8 2000.3340 MAY 146.5 104.8 53.5 20.6 16.4 11.5 2000.4173 JUN 147.4 104.0 52.5 21.0 16.4 11.4 2000.5007 JUL 143.5 102.7 51.9 21.5 16.5 11.1 2000.5840 AUG 141.8 101.6 51.9 21.7 16.4 10.7 2000.6673 SEP 140.5 100.9 51.5 21.0 16.2 10.0 2000.7507 OCT 139.8 100.6 50.5 20.9 15.9 9.4 2000.8340 NOV 138.9 100.1 48.9 21.1 15.8 9.3 2000.9173 DEC 138.6 99.5 46.2 21.5 15.8 9.3 2001.0007 JAN 137.5 98.9 42.9 22.3 15.7 9.0 2001.0840 FEB 136.4 98.2 40.1 22.1 15.3 8.7 2001.1673 MAR 135.6 97.7 37.1 21.1 14.9 8.9 2001.2507 APR 138.9 97.1 35.3 20.4 14.6 9.2 2001.3340 MAY 141.4 96.3 33.8 20.0 14.5 9.7 2001.4173 JUN 139.6 95.3 33.2 19.5 14.4 9.9 2001.5007 JUL 136.1 93.8 31.7 19.4 14.3 10.1 2001.5840 AUG 133.3 91.8 30.1 19.2 14.4 10.1 2001.6673 SEP 131.4 90.1 29.0 18.9 14.7 10.4 2001.7507 OCT 130.7 88.9 28.5 18.6 15.1 11.1 2001.8340 NOV 129.8 87.8 28.5 18.5 15.4 11.2 2001.9173 DEC 129.0 86.3 28.8 19.0 15.5 11.0 2002.0007 JAN 130.5 84.6 29.4 19.8 15.7 11.5 2002.0840 FEB 132.5 83.3 30.4 21.4 16.2 12.0 2002.1673 MAR 132.7 82.2 31.2 22.7 16.6 12.2 2002.2507 APR 130.1 80.7 32.0 23.3 16.8 12.5 2002.3340 MAY 128.5 79.0 32.8 24.4 17.1 12.7 2002.4173 JUN 127.9 77.2 33.6 24.9 17.3 13.0 2002.5007 JUL 125.5 75.6 34.3 24.2 17.3 13.3 2002.5840 AUG 122.5 74.3 32.9 24.1 17.2 13.4 2002.6673 SEP 118.7 73.1 31.3 23.2 17.1 13.4 2002.7507 OCT 114.6 71.9 30.7 21.4 17.0 13.2 2002.8340 NOV 111.7 70.5 29.8 21.7 17.1 13.2 2002.9173 DEC 109.9 68.8 28.5 22.5 17.1 13.1 2003.0007 JAN 106.2 66.8 27.1 22.6 17.0 12.2 2003.0840 FEB 99.8 64.5 26.3 22.1 16.8 11.8 2003.1673 MAR 93.1 62.1 25.7 21.5 16.6 11.8 2003.2507 APR 89.8 60.2 25.9 21.3 16.7 12.0 2003.3340 MAY 88.9 58.5 25.4 22.0 17.0 12.2 2003.4173 JUN 88.2 57.0 25.0 22.9 17.3 12.3 2003.5007 JUL 86.8 55.5 25.4 23.1 17.6 12.5 2003.5840 AUG 85.1 53.9 24.9 23.0 17.9 12.5 2003.6673 SEP 81.9 52.2 22.0 23.0 18.0 12.5 2003.7507 OCT 78.7 50.6 19.6 22.6 18.0 12.1 2003.8340 NOV 77.5 48.9 18.3 21.2 17.9 12.1 2003.9173 DEC 75.2 47.0 16.7 21.2 17.7 12.2 2004.0007 JAN 74.3 45.3 15.3 21.2 17.8 12.9 2004.0840 FEB 73.2 44.1 14.2 21.2 18.1 13.4 2004.1673 MAR 70.8 43.0 13.6 21.0 18.2 13.4 2004.2507 APR 69.0 41.7 13.2 21.6 18.0 13.3 2004.3340 MAY 68.0 40.2 12.1 22.5 17.7 13.2 2004.4173 JUN 66.4 38.8 10.9 22.8 17.4 13.3 2004.5007 JUL 64.4 37.4 10.2 22.7 17.2 14.0 2004.5840 AUG 61.6 36.0 9.8 22.2 17.3 13.5 2004.6673 SEP 58.1 34.5 9.4 22.0 17.4 13.1 2004.7507 OCT 54.3 33.1 9.4 21.8 17.4 12.6 2004.8340 NOV 51.4 31.9 9.1 21.8 17.2 12.3 2004.9173 DEC 50.6 31.1 8.8 22.1 17.0 12.0 2005.0007 JAN 49.6 30.1 8.6 22.3 16.6 11.6 2005.0840 FEB 47.6 28.8 8.6 22.7 16.5 10.6 2005.1673 MAR 45.4 27.3 7.4 23.2 16.3 9.8 2005.2507 APR 43.3 26.2 7.2 23.8 16.4 9.8 2005.3340 MAY 42.8 25.3 6.9 24.2 16.5 9.9 2005.4173 JUN 41.5 24.3 6.6 24.4 16.5 9.7 2005.5007 JUL 39.6 23.3 6.4 24.2 16.4 9.8 2005.5840 AUG 39.0 22.4 6.0 23.6 16.3 10.0 2005.6673 SEP 38.4 21.5 5.5 22.7 16.1 10.2 2005.7507 OCT 36.4 20.3 5.1 21.9 15.9 10.4 2005.8340 NOV 34.5 19.2 4.7 21.4 15.9 10.4 2005.9173 DEC 32.6 18.0 4.3 21.1 16.0 10.3 2006.0007 JAN 30.7 16.9 3.9 20.9 16.1 10.5 2006.0840 FEB 28.8 15.8 3.5 20.6 16.2 10.8 2006.1673 MAR 27.0 14.7 3.1 20.5 16.0 10.9 2006.2507 APR 25.2 13.7 2.8 20.7 15.7 11.0 2006.3340 MAY 23.6 12.7 2.4 20.7 15.5 11.4 2006.4173 JUN 22.0 11.7 2.1 20.7 15.2 11.9 2006.5007 JUL 20.4 10.8 1.7 20.3 15.0 11.6 2006.5840 AUG 19.0 10.0 1.4 19.6 14.7 11.5 2006.6673 SEP 17.7 9.2 1.2 18.8 14.5 11.2 2006.7507 OCT 16.5 8.5 0.9 17.9 14.4 10.7 2006.8340 NOV 15.5 7.9 0.7 17.5 14.2 10.0 2006.9173 DEC 14.5 7.3 0.5 17.4 14.0 9.8 2007.0007 JAN 13.7 6.8 0.3 17.3 13.9 9.7 2007.0840 FEB 13.1 6.5 0.2 16.9 13.8 9.6 2007.1673 MAR 12.7 6.2 0.1 16.4 13.7 9.7 2007.2507 APR 12.4 6.0 0.0 16.4 13.5 9.7 2007.3340 MAY 12.3 6.0 0.0 16.2 13.3 9.6 2007.4173 JUN 12.9 6.4 0.4 15.9 13.0 9.5 2007.5007 JUL 14.3 7.1 0.8 15.4 12.6 9.3 2007.5840 AUG 15.5 7.8 1.1 14.9 12.2 9.0 2007.6673 SEP 16.7 8.5 1.6 14.4 11.7 8.7 2007.7507 OCT 18.2 9.2 1.7 13.9 11.3 8.4 2007.8340 NOV 20.6 10.2 2.2 13.5 11.0 8.2 2007.9173 DEC 23.0 11.2 2.8 13.0 10.6 8.0 2008.0007 JAN 25.1 12.3 3.0 12.6 10.3 7.7 2008.0840 FEB 28.4 13.6 3.1 12.2 9.9 7.5 2008.1673 MAR 32.5 15.0 3.3 11.9 9.7 7.4 2008.2507 APR 38.7 16.8 3.2 11.6 9.4 7.2 2008.3340 MAY 44.3 18.8 3.3 11.4 9.2 7.1 2008.4173 JUN 48.5 20.9 4.0 11.2 9.1 7.0 2008.5007 JUL 54.8 23.1 4.1 11.1 9.0 6.9 2008.5840 AUG 61.7 25.6 4.2 11.1 9.0 6.9 2008.6673 SEP 68.1 28.1 4.7 11.3 9.1 6.9 2008.7507 OCT 75.9 30.7 4.7 11.6 9.3 7.1 2008.8340 NOV 84.7 33.9 5.0 11.7 9.4 7.4 2008.9173 DEC 91.4 37.1 5.7 11.9 9.5 7.5 2009.0007 JAN 96.4 40.6 6.6 12.0 9.6 7.5 2009.0840 FEB 101.2 44.1 7.4 12.1 9.6 7.3 2009.1673 MAR 106.0 47.5 8.8 12.2 9.7 7.2 2009.2507 APR 111.3 50.8 9.5 12.6 9.8 7.0 2009.3340 MAY 117.0 54.2 9.6 12.9 10.1 6.9 2009.4173 JUN 122.3 57.9 11.1 13.3 10.5 7.1 2009.5007 JUL 126.8 61.7 12.2 13.8 10.8 7.5 2009.5840 AUG 134.2 65.3 13.2 14.6 11.1 7.8 2009.6673 SEP 142.0 68.8 14.4 15.8 11.4 7.6 2009.7507 OCT 146.7 72.2 14.9 16.2 11.6 7.6 2009.8340 NOV 148.5 75.3 15.4 16.4 11.7 7.5 2009.9173 DEC 151.8 78.1 16.0 16.9 11.9 7.5 2010.0007 JAN 155.5 80.4 16.3 18.1 12.2 7.5 2010.0840 FEB 159.3 82.5 16.7 19.0 12.6 7.6 2010.1673 MAR 164.8 84.8 16.6 19.2 12.8 7.6 2010.2507 APR 168.2 87.0 16.1 19.3 13.0 7.7 2010.3340 MAY 169.9 89.3 15.7 19.1 13.2 7.6 2010.4173 JUN 173.9 91.5 16.1 18.7 13.3 7.6 2010.5007 JUL 178.8 93.5 16.6 18.6 13.3 7.7 2010.5840 AUG 181.8 95.3 17.7 19.0 13.5 7.9 2010.6673 SEP 183.9 97.4 19.5 18.9 13.6 8.1 2010.7507 OCT 186.7 99.2 20.7 17.9 13.6 8.5 2010.8340 NOV 189.2 100.5 22.0 18.0 13.8 8.6 2010.9173 DEC 191.5 101.5 24.3 18.6 14.1 8.6 2011.0007 JAN 192.9 101.6 27.0 19.2 14.3 8.9 2011.0840 FEB 194.3 102.1 29.8 19.7 14.8 9.3 2011.1673 MAR 194.4 103.1 31.4 20.4 15.1 9.5 2011.2507 APR 193.8 103.7 32.8 20.4 15.2 9.5 2011.3340 MAY 195.2 104.1 35.2 20.4 15.2 9.7 2011.4173 JUN 195.8 103.4 37.0 20.6 15.2 9.9 2011.5007 JUL 192.6 102.0 39.4 20.9 15.4 10.4 2011.5840 AUG 188.0 101.0 41.1 21.3 15.4 11.0 2011.6673 SEP 183.4 100.3 42.5 21.3 15.3 11.6 2011.7507 OCT 181.2 100.0 43.7 21.5 15.1 11.2 2011.8340 NOV 180.5 99.6 43.6 21.7 15.1 11.1 2011.9173 DEC 179.4 99.0 43.1 22.1 15.1 10.6 2012.0007 JAN 178.2 98.4 43.9 22.9 15.0 10.1 2012.0840 FEB 176.8 97.7 45.7 22.6 14.7 9.8 2012.1673 MAR 176.1 97.2 45.9 21.4 14.4 10.0 2012.2507 APR 175.0 96.7 45.0 20.7 14.3 10.0 2012.3340 MAY 173.8 95.8 44.3 20.1 14.2 10.2 2012.4173 JUN 172.1 94.8 44.8 19.7 14.1 10.5 2012.5007 JUL 169.5 93.4 45.4 19.6 14.1 10.5 2012.5840 AUG 165.3 91.3 44.1 19.4 14.1 10.4 2012.6673 SEP 162.0 89.6 43.5 19.2 14.4 10.4 2012.7507 OCT 158.7 88.5 44.5 19.0 14.7 10.4 2012.8340 NOV 154.4 87.4 45.5 19.0 14.9 10.2 2012.9173 DEC 150.8 85.9 44.4 19.5 14.8 9.8 2013.0007 JAN 146.5 84.2 42.4 20.5 14.9 10.1 2013.0840 FEB 142.9 82.9 41.5 22.1 15.3 10.6 2013.1673 MAR 142.2 81.9 41.2 23.5 15.6 10.6 2013.2507 APR 138.9 80.4 39.2 24.1 15.8 10.8 2013.3340 MAY 136.8 78.7 34.7 25.3 16.1 10.9 2013.4173 JUN 135.9 76.9 33.8 25.8 16.3 11.1 2013.5007 JUL 132.9 75.3 35.3 25.0 16.3 11.4 2013.5840 AUG 129.3 74.0 34.6 24.9 16.2 11.6 2013.6673 SEP 125.3 72.8 32.7 24.1 16.2 11.7 2013.7507 OCT 121.0 71.6 31.7 22.2 16.1 11.7 2013.8340 NOV 117.5 70.3 30.8 22.5 16.2 11.9 2013.9173 DEC 115.3 68.5 29.3 23.2 16.3 11.7 2014.0007 JAN 111.4 66.6 27.6 23.3 16.3 10.9 2014.0840 FEB 104.9 64.3 26.5 22.8 16.1 10.6 2014.1673 MAR 98.0 62.0 26.2 22.1 15.9 10.7 2014.2507 APR 94.1 60.0 26.5 22.0 15.9 10.7 2014.3340 MAY 93.1 58.3 25.7 22.9 16.1 10.6 2014.4173 JUN 92.2 56.8 24.2 23.8 16.4 10.7 2014.5007 JUL 89.9 55.4 24.3 24.0 16.6 10.7 2014.5840 AUG 87.6 53.7 23.8 24.0 16.8 10.6 2014.6673 SEP 83.8 52.0 22.7 24.0 16.9 10.5 2014.7507 OCT 80.3 50.5 21.8 23.6 16.9 10.2 2014.8340 NOV 76.6 48.8 20.4 22.7 16.9 10.3 2014.9173 DEC 71.1 46.9 18.9 22.9 16.8 10.5 2015.0007 JAN 69.8 45.2 16.7 23.1 16.9 11.3 2015.0840 FEB 70.3 44.0 14.9 23.2 17.2 11.8 2015.1673 MAR 69.9 42.9 13.7 22.6 17.3 11.9 2015.2507 APR 69.7 41.6 11.8 21.6 17.2 12.1 2015.3340 MAY 68.9 40.1 10.3 21.3 17.1 12.2 2015.4173 JUN 66.9 38.7 9.3 21.8 16.9 12.4 2015.5007 JUL 64.3 37.3 8.5 21.8 16.7 13.2 2015.5840 AUG 61.0 35.9 7.7 22.2 16.8 13.0 2015.6673 SEP 56.5 34.5 7.6 22.6 16.9 12.7 2015.7507 OCT 52.1 33.0 7.7 22.4 16.9 13.0 2015.8340 NOV 49.0 31.9 7.3 22.4 16.7 12.7 2015.9173 DEC 49.9 31.0 7.3 22.8 16.5 12.4 2016.0007 JAN 49.0 30.0 7.2 23.0 16.1 12.0 2016.0840 FEB 46.4 28.7 7.1 23.6 15.8 11.1 2016.1673 MAR 44.1 27.3 6.5 24.2 15.6 10.4 2016.2507 APR 42.0 26.2 6.3 25.0 15.5 10.5 2016.3340 MAY 41.0 25.3 5.9 25.5 15.5 10.6 2016.4173 JUN 39.5 24.2 5.4 25.7 15.5 10.5 2016.5007 JUL 38.9 23.3 5.0 25.6 15.4 10.6 2016.5840 AUG 38.3 22.3 4.4 25.0 15.3 10.9 2016.6673 SEP 37.9 21.5 3.7 24.1 15.1 11.0 2016.7507 OCT 37.1 20.4 3.5 23.1 14.9 11.2 2016.8340 NOV 36.1 19.5 3.4 22.6 15.0 11.1 2016.9173 DEC 34.9 18.7 3.2 22.2 15.2 11.0 2017.0007 JAN 33.5 17.9 3.2 21.9 15.4 11.1 2017.0840 FEB 31.8 16.9 2.6 21.5 15.5 11.3 2017.1673 MAR 29.9 16.0 1.9 20.8 15.5 11.4 2017.2507 APR 27.1 15.2 1.5 20.0 15.3 11.4 2017.3340 MAY 24.6 14.2 1.4 20.1 15.1 11.7 2017.4173 JUN 22.2 13.0 1.1 20.2 14.9 11.9 2017.5007 JUL 20.3 11.8 0.7 19.9 14.7 11.6 2017.5840 AUG 19.2 10.8 0.5 19.5 14.6 11.5 2017.6673 SEP 19.0 10.0 0.4 19.0 14.6 11.1 2017.7507 OCT 18.5 9.3 0.4 18.2 14.6 10.6 2017.8340 NOV 18.2 8.7 0.3 17.3 14.5 9.8 2017.9173 DEC 16.8 8.2 0.2 17.4 14.4 9.4 2018.0007 JAN 15.9 7.7 0.1 17.5 14.3 9.3 2018.0840 FEB 15.9 7.2 0.0 17.6 14.2 9.3 2018.1673 MAR 15.1 6.7 0.0 17.6 14.1 9.3