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% 1999.0840 FEB 87.8 84.7 81.3 12.9 12.1 11.7 1999.1673 MAR 93.6 87.1 79.8 13.1 12.4 11.9 1999.2507 APR 99.9 89.3 76.6 13.7 12.6 12.0 1999.3340 MAY 106.5 91.7 72.0 14.2 12.8 12.0 1999.4173 JUN 111.1 93.9 68.3 15.3 12.9 11.9 1999.5007 JUL 114.5 95.9 66.7 15.9 12.9 11.7 1999.5840 AUG 119.1 97.8 66.1 16.2 13.1 11.4 1999.6673 SEP 124.9 99.9 67.0 16.4 13.2 11.3 1999.7507 OCT 130.0 101.7 66.7 16.8 13.3 11.7 1999.8340 NOV 132.7 103.0 64.8 17.5 13.5 11.3 1999.9173 DEC 134.0 103.8 63.0 18.0 13.7 11.2 2000.0007 JAN 134.8 103.9 60.5 18.7 14.1 11.4 2000.0840 FEB 136.3 104.4 60.1 19.2 14.5 11.8 2000.1673 MAR 139.8 105.3 61.6 19.1 14.8 11.6 2000.2507 APR 142.7 105.9 61.9 19.3 14.9 11.3 2000.3340 MAY 147.7 106.2 62.2 19.0 14.9 10.9 2000.4173 JUN 148.5 105.5 61.1 18.3 14.9 10.6 2000.5007 JUL 144.0 104.1 59.8 18.7 15.1 10.3 2000.5840 AUG 139.3 102.9 58.9 19.0 15.2 9.9 2000.6673 SEP 138.1 102.2 58.2 18.7 15.0 9.2 2000.7507 OCT 139.3 101.8 57.6 18.9 14.9 8.7 2000.8340 NOV 139.8 101.3 56.5 19.2 14.9 8.6 2000.9173 DEC 139.5 100.7 53.6 19.6 14.9 8.6 2001.0007 JAN 138.4 100.1 50.0 20.3 14.7 8.2 2001.0840 FEB 136.6 99.3 46.7 20.2 14.5 7.9 2001.1673 MAR 132.8 98.8 43.5 19.5 14.2 8.1 2001.2507 APR 133.1 98.2 41.7 19.2 14.1 8.5 2001.3340 MAY 135.9 97.3 40.1 18.9 14.1 9.0 2001.4173 JUN 134.3 96.4 39.3 18.5 14.0 9.2 2001.5007 JUL 130.4 94.9 37.7 18.4 14.0 9.4 2001.5840 AUG 127.7 92.8 35.8 18.1 14.0 9.4 2001.6673 SEP 126.0 91.0 34.5 17.8 14.3 9.8 2001.7507 OCT 125.3 89.9 33.9 17.7 14.6 10.6 2001.8340 NOV 124.6 88.8 33.7 18.6 14.7 10.4 2001.9173 DEC 124.0 87.2 33.8 19.3 14.6 10.0 2002.0007 JAN 125.6 85.5 34.0 20.2 14.7 10.4 2002.0840 FEB 127.7 84.1 34.5 21.8 15.1 11.1 2002.1673 MAR 128.1 83.0 35.1 23.2 15.4 11.1 2002.2507 APR 125.9 81.5 35.5 23.8 15.6 11.1 2002.3340 MAY 124.4 79.7 36.2 25.0 15.9 11.2 2002.4173 JUN 123.9 77.9 36.5 25.5 16.1 11.4 2002.5007 JUL 121.8 76.2 36.7 24.7 16.1 11.8 2002.5840 AUG 118.9 74.9 36.1 24.6 16.1 12.1 2002.6673 SEP 115.3 73.7 34.4 23.8 16.0 11.8 2002.7507 OCT 111.3 72.4 33.7 21.9 15.9 11.4 2002.8340 NOV 108.5 71.1 32.7 20.4 16.0 11.3 2002.9173 DEC 106.8 69.3 31.1 21.0 16.1 11.4 2003.0007 JAN 103.4 67.2 29.2 21.2 16.1 11.3 2003.0840 FEB 97.1 65.0 28.0 20.8 16.0 11.0 2003.1673 MAR 91.2 62.5 27.2 20.2 15.8 11.0 2003.2507 APR 88.2 60.6 27.4 19.8 15.7 11.0 2003.3340 MAY 87.3 58.9 26.9 20.2 15.9 11.1 2003.4173 JUN 86.5 57.4 26.2 20.8 16.1 11.2 2003.5007 JUL 85.2 55.9 25.3 20.8 16.3 11.2 2003.5840 AUG 83.6 54.2 23.7 20.7 16.5 11.1 2003.6673 SEP 80.6 52.5 20.7 20.6 16.6 11.0 2003.7507 OCT 79.6 50.8 18.3 20.3 16.6 10.7 2003.8340 NOV 78.8 49.1 17.1 20.0 16.6 10.8 2003.9173 DEC 76.4 47.2 15.7 20.1 16.5 11.0 2004.0007 JAN 75.5 45.5 14.3 20.5 16.7 11.7 2004.0840 FEB 74.3 44.3 13.2 20.6 17.0 12.2 2004.1673 MAR 71.9 43.2 12.7 20.4 17.1 12.3 2004.2507 APR 69.6 41.9 12.2 21.4 17.1 12.3 2004.3340 MAY 68.0 40.4 11.1 22.2 16.9 12.3 2004.4173 JUN 67.1 38.9 10.0 22.5 16.7 12.5 2004.5007 JUL 65.6 37.5 9.3 22.3 16.7 13.3 2004.5840 AUG 62.7 36.1 9.0 21.9 16.7 12.7 2004.6673 SEP 59.2 34.7 9.2 21.5 16.9 12.5 2004.7507 OCT 55.5 33.2 9.5 21.3 16.8 12.1 2004.8340 NOV 52.5 32.0 9.6 21.2 16.6 11.7 2004.9173 DEC 51.0 31.2 9.3 21.3 16.4 11.3 2005.0007 JAN 50.1 30.2 9.3 21.3 16.0 10.7 2005.0840 FEB 48.4 28.8 9.5 21.5 15.7 9.6 2005.1673 MAR 46.1 27.4 7.9 21.8 15.4 8.5 2005.2507 APR 44.2 26.3 7.5 21.9 15.3 8.3 2005.3340 MAY 43.6 25.4 7.4 22.1 15.3 8.1 2005.4173 JUN 42.2 24.4 7.1 22.2 15.3 7.8 2005.5007 JUL 40.0 23.4 6.8 21.8 15.1 7.7 2005.5840 AUG 39.4 22.5 6.4 21.2 15.0 7.9 2005.6673 SEP 38.8 21.6 6.0 20.4 14.8 8.2 2005.7507 OCT 36.8 20.4 5.6 19.7 14.7 8.5 2005.8340 NOV 34.8 19.3 5.1 19.4 14.8 8.7 2005.9173 DEC 32.9 18.1 4.7 19.3 15.0 8.8 2006.0007 JAN 30.9 17.0 4.2 19.4 15.2 9.2 2006.0840 FEB 29.1 15.9 3.8 19.3 15.4 9.7 2006.1673 MAR 27.2 14.8 3.4 19.8 15.3 9.9 2006.2507 APR 25.4 13.7 3.0 20.1 15.2 10.1 2006.3340 MAY 23.7 12.7 2.6 20.3 15.0 10.6 2006.4173 JUN 22.1 11.8 2.2 20.3 14.8 11.3 2006.5007 JUL 20.6 10.9 1.9 20.0 14.7 11.7 2006.5840 AUG 19.1 10.0 1.6 19.5 14.6 11.5 2006.6673 SEP 17.8 9.2 1.3 19.0 14.6 11.1 2006.7507 OCT 16.6 8.5 1.0 18.2 14.6 10.6 2006.8340 NOV 15.5 7.9 0.7 17.4 14.6 9.8 2006.9173 DEC 14.6 7.3 0.5 17.3 14.4 9.5 2007.0007 JAN 13.8 6.9 0.4 17.2 14.3 9.4 2007.0840 FEB 13.1 6.5 0.2 17.3 14.2 9.4 2007.1673 MAR 12.7 6.2 0.1 17.1 14.1 9.4 2007.2507 APR 12.4 6.0 0.0 16.6 13.7 9.2 2007.3340 MAY 12.3 6.0 0.0 16.1 13.2 9.0 2007.4173 JUN 12.9 6.4 0.4 15.6 12.8 8.7 2007.5007 JUL 14.3 7.1 0.8 15.0 12.4 8.5 2007.5840 AUG 15.5 7.8 1.1 14.5 11.9 8.3 2007.6673 SEP 16.7 8.5 1.6 14.1 11.5 8.1 2007.7507 OCT 18.2 9.2 1.7 13.6 11.1 7.9 2007.8340 NOV 20.6 10.2 2.2 13.2 10.8 7.8 2007.9173 DEC 23.0 11.2 2.8 12.8 10.4 7.6 2008.0007 JAN 25.1 12.3 3.0 12.4 10.1 7.5 2008.0840 FEB 28.4 13.6 3.1 12.1 9.8 7.3 2008.1673 MAR 32.5 15.0 3.3 11.8 9.6 7.2 2008.2507 APR 38.7 16.8 3.2 11.6 9.4 7.1 2008.3340 MAY 44.3 18.8 3.3 11.4 9.2 7.0 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