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% 2000.1673 MAR 121.4 117.4 111.9 16.5 15.5 14.9 2000.2507 APR 127.7 117.8 108.2 16.6 15.6 14.5 2000.3340 MAY 134.4 118.1 105.2 16.8 15.6 14.3 2000.4173 JUN 137.4 117.3 103.8 17.0 15.6 14.0 2000.5007 JUL 137.2 115.5 102.5 17.6 15.8 13.5 2000.5840 AUG 138.3 113.7 98.8 17.9 15.8 13.0 2000.6673 SEP 140.2 112.3 94.5 18.2 15.6 11.9 2000.7507 OCT 140.7 111.7 92.6 18.6 15.4 11.1 2000.8340 NOV 139.7 111.2 92.6 18.9 15.4 11.0 2000.9173 DEC 138.6 110.4 91.6 19.5 15.4 11.0 2001.0007 JAN 137.2 109.6 90.7 20.3 15.3 10.6 2001.0840 FEB 134.4 108.8 87.8 20.2 15.0 10.1 2001.1673 MAR 130.6 108.1 83.5 19.4 14.6 9.9 2001.2507 APR 128.7 107.4 81.3 19.0 14.5 9.9 2001.3340 MAY 126.6 106.4 79.3 18.7 14.4 10.2 2001.4173 JUN 123.0 105.2 77.4 18.4 14.3 10.4 2001.5007 JUL 122.2 103.7 75.6 18.4 14.3 10.5 2001.5840 AUG 122.1 101.7 72.7 18.1 14.3 10.7 2001.6673 SEP 121.3 99.8 70.7 17.8 14.6 11.1 2001.7507 OCT 121.7 98.3 68.9 18.1 14.9 11.8 2001.8340 NOV 122.9 96.9 67.5 18.5 15.1 11.9 2001.9173 DEC 123.7 95.2 66.4 18.4 15.0 11.5 2002.0007 JAN 123.3 93.2 65.6 18.3 15.2 11.4 2002.0840 FEB 122.3 91.4 63.7 18.7 15.6 11.6 2002.1673 MAR 120.8 89.9 61.7 19.8 15.9 12.1 2002.2507 APR 118.0 88.1 59.9 20.4 16.1 12.4 2002.3340 MAY 118.8 86.3 57.6 21.4 16.4 12.3 2002.4173 JUN 120.1 84.3 54.6 21.9 16.6 12.2 2002.5007 JUL 118.5 82.3 50.9 21.4 16.6 12.4 2002.5840 AUG 115.6 80.7 49.1 21.3 16.6 12.7 2002.6673 SEP 112.4 79.4 48.1 21.1 16.5 12.8 2002.7507 OCT 109.3 78.0 46.7 20.8 16.4 12.6 2002.8340 NOV 105.8 76.4 45.5 20.7 16.5 12.6 2002.9173 DEC 101.5 74.4 43.8 21.0 16.5 12.6 2003.0007 JAN 98.0 72.2 41.2 21.1 16.5 12.7 2003.0840 FEB 95.1 69.9 38.9 21.0 16.3 12.1 2003.1673 MAR 93.5 67.3 37.4 20.8 16.1 11.8 2003.2507 APR 91.6 65.0 36.8 20.5 16.1 11.9 2003.3340 MAY 89.0 63.1 34.9 21.2 16.3 12.1 2003.4173 JUN 86.6 61.6 34.1 22.0 16.6 12.2 2003.5007 JUL 85.1 59.8 32.9 22.0 16.8 12.4 2003.5840 AUG 84.9 58.0 31.3 21.9 17.0 12.4 2003.6673 SEP 84.9 56.1 28.6 22.5 17.1 12.2 2003.7507 OCT 85.0 54.2 24.8 22.5 17.1 11.8 2003.8340 NOV 84.3 52.2 22.2 22.4 17.0 11.7 2003.9173 DEC 82.2 50.2 20.6 22.7 16.9 11.7 2004.0007 JAN 80.8 48.3 18.8 23.0 17.0 12.3 2004.0840 FEB 79.4 47.0 17.5 23.1 17.3 12.7 2004.1673 MAR 76.8 45.9 16.8 22.4 17.5 12.9 2004.2507 APR 74.4 44.8 16.5 21.5 17.4 12.9 2004.3340 MAY 72.9 43.4 15.6 21.4 17.2 12.9 2004.4173 JUN 72.1 41.7 14.1 21.9 16.9 13.0 2004.5007 JUL 70.6 40.0 12.8 21.9 16.8 13.5 2004.5840 AUG 67.8 38.4 11.8 22.0 16.9 12.8 2004.6673 SEP 64.8 36.8 11.4 22.4 17.0 12.6 2004.7507 OCT 61.5 35.3 11.4 22.2 16.9 12.6 2004.8340 NOV 58.5 34.1 11.7 22.2 16.8 12.3 2004.9173 DEC 58.0 33.2 11.5 22.4 16.5 12.0 2005.0007 JAN 56.5 32.1 11.2 22.6 16.1 11.5 2005.0840 FEB 54.9 30.8 11.5 23.1 15.9 10.5 2005.1673 MAR 52.4 29.2 11.2 23.6 15.7 9.6 2005.2507 APR 49.6 27.8 10.1 24.2 15.6 9.5 2005.3340 MAY 47.9 26.8 10.4 24.6 15.7 9.4 2005.4173 JUN 45.9 25.8 11.0 24.8 15.6 9.3 2005.5007 JUL 42.9 24.9 10.6 24.6 15.5 9.3 2005.5840 AUG 40.4 24.0 10.3 24.1 15.4 9.6 2005.6673 SEP 39.4 23.1 10.0 23.2 15.2 9.8 2005.7507 OCT 37.3 21.8 9.2 22.4 15.1 10.1 2005.8340 NOV 35.3 20.5 8.5 22.0 15.1 10.2 2005.9173 DEC 33.3 19.3 7.8 21.7 15.2 10.2 2006.0007 JAN 31.4 18.0 7.0 21.4 15.5 10.5 2006.0840 FEB 29.4 16.8 6.3 21.1 15.6 10.8 2006.1673 MAR 27.6 15.6 5.6 20.6 15.5 11.0 2006.2507 APR 25.7 14.5 5.0 20.1 15.3 11.1 2006.3340 MAY 24.0 13.4 4.3 20.2 15.1 11.6 2006.4173 JUN 22.3 12.3 3.7 20.2 14.9 11.9 2006.5007 JUL 20.8 11.3 3.1 19.8 14.7 11.5 2006.5840 AUG 19.3 10.4 2.6 19.2 14.6 11.3 2006.6673 SEP 17.9 9.5 2.1 18.5 14.5 11.0 2006.7507 OCT 16.7 8.7 1.6 17.6 14.5 10.9 2006.8340 NOV 15.6 8.1 1.2 17.8 14.4 11.1 2006.9173 DEC 14.6 7.4 0.9 17.7 14.3 10.9 2007.0007 JAN 13.8 6.9 0.6 17.6 14.1 10.8 2007.0840 FEB 13.2 6.5 0.3 17.3 14.1 10.9 2007.1673 MAR 12.7 6.2 0.2 16.9 13.9 11.0 2007.2507 APR 12.4 6.0 0.1 16.4 13.5 10.6 2007.3340 MAY 12.3 6.0 0.0 15.9 13.1 10.3 2007.4173 JUN 12.9 6.3 0.4 15.4 12.6 9.9 2007.5007 JUL 14.3 6.9 0.7 14.9 12.2 9.6 2007.5840 AUG 15.5 7.6 1.0 14.4 11.8 9.3 2007.6673 SEP 16.7 8.2 1.5 13.9 11.4 8.9 2007.7507 OCT 18.1 9.0 1.7 13.5 11.1 8.6 2007.8340 NOV 20.6 9.9 2.2 13.1 10.7 8.3 2007.9173 DEC 22.9 10.9 2.7 12.7 10.4 8.1 2008.0007 JAN 25.0 12.0 2.9 12.4 10.1 7.8 2008.0840 FEB 28.3 13.2 3.1 12.0 9.8 7.6 2008.1673 MAR 32.2 14.6 3.3 11.8 9.6 7.4 2008.2507 APR 38.3 16.3 3.3 11.5 9.4 7.2 2008.3340 MAY 43.7 18.3 3.3 11.3 9.2 7.1 2008.4173 JUN 47.9 20.4 4.0 11.2 9.1 7.0 2008.5007 JUL 53.9 22.6 4.2 11.1 9.0 6.9 2008.5840 AUG 60.9 25.0 4.3 11.1 9.0 6.9 2008.6673 SEP 67.5 27.6 4.8 11.3 9.1 6.9 2008.7507 OCT 75.1 30.2 4.6 11.6 9.3 7.1 2008.8340 NOV 83.9 33.0 4.8 11.7 9.4 7.4 2008.9173 DEC 90.9 36.2 5.6 11.9 9.5 7.5 2009.0007 JAN 96.0 39.9 6.6 12.0 9.6 7.5 2009.0840 FEB 100.8 43.5 7.3 12.1 9.6 7.3 2009.1673 MAR 105.5 46.9 8.6 12.2 9.7 7.2 2009.2507 APR 110.7 50.3 9.5 12.6 9.8 7.0 2009.3340 MAY 116.4 53.7 9.6 12.9 10.1 6.9 2009.4173 JUN 121.8 57.4 11.1 13.3 10.5 7.1 2009.5007 JUL 126.2 61.0 12.2 13.8 10.8 7.5 2009.5840 AUG 134.2 64.5 13.2 14.6 11.1 7.8 2009.6673 SEP 141.9 67.7 14.4 15.8 11.4 7.6 2009.7507 OCT 146.6 71.2 14.9 16.2 11.6 7.6 2009.8340 NOV 148.6 74.6 15.4 16.4 11.7 7.5 2009.9173 DEC 151.8 77.4 16.0 16.9 11.9 7.5 2010.0007 JAN 155.5 79.8 16.4 18.1 12.2 7.5 2010.0840 FEB 159.3 81.9 16.7 19.0 12.6 7.6 2010.1673 MAR 164.8 84.2 16.6 19.2 12.8 7.6 2010.2507 APR 168.2 86.5 16.1 19.3 13.0 7.7 2010.3340 MAY 169.9 88.9 15.7 19.1 13.2 7.6 2010.4173 JUN 173.9 91.1 16.1 18.7 13.3 7.6 2010.5007 JUL 178.8 93.2 16.6 18.6 13.3 7.7 2010.5840 AUG 181.8 95.2 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 99.4 20.7 17.9 13.6 8.5 2010.8340 NOV 189.2 100.7 22.0 18.0 13.8 8.6 2010.9173 DEC 191.5 101.6 24.3 18.6 14.1 8.6 2011.0007 JAN 192.9 101.8 27.0 19.2 14.3 8.9 2011.0840 FEB 194.3 102.2 29.8 19.7 14.8 9.3 2011.1673 MAR 194.4 103.0 31.5 20.4 15.1 9.5 2011.2507 APR 193.8 103.6 32.8 20.4 15.2 9.5 2011.3340 MAY 195.2 104.2 35.3 20.4 15.2 9.7 2011.4173 JUN 195.8 103.7 37.1 20.6 15.2 9.9 2011.5007 JUL 192.6 102.3 39.5 20.9 15.4 10.4 2011.5840 AUG 188.0 101.0 41.2 21.3 15.4 11.0 2011.6673 SEP 183.4 100.2 41.9 21.3 15.3 11.6 2011.7507 OCT 181.2 100.0 43.4 21.5 15.1 11.2 2011.8340 NOV 180.5 99.8 43.7 21.7 15.1 11.1 2011.9173 DEC 179.4 99.1 43.2 22.1 15.1 10.6 2012.0007 JAN 178.2 98.5 43.3 22.9 15.0 10.1 2012.0840 FEB 176.8 98.0 45.1 22.6 14.7 9.8 2012.1673 MAR 176.1 97.4 46.0 21.4 14.4 10.0 2012.2507 APR 175.0 96.8 45.4 20.7 14.3 10.0 2012.3340 MAY 173.8 95.9 44.6 20.1 14.2 10.2 2012.4173 JUN 172.1 94.9 44.5 19.7 14.1 10.5 2012.5007 JUL 169.5 93.7 45.1 19.6 14.1 10.5 2012.5840 AUG 165.3 92.0 44.1 19.4 14.1 10.4 2012.6673 SEP 162.0 90.2 43.4 19.2 14.4 10.4 2012.7507 OCT 158.7 88.8 44.4 19.0 14.7 10.4 2012.8340 NOV 154.4 87.7 45.5 19.0 14.9 10.2 2012.9173 DEC 150.8 86.3 44.5 19.5 14.8 9.8 2013.0007 JAN 146.5 84.6 42.5 20.5 14.9 10.1 2013.0840 FEB 142.9 83.1 41.6 22.1 15.3 10.6 2013.1673 MAR 142.2 81.9 41.3 23.5 15.6 10.6 2013.2507 APR 138.9 80.6 39.2 24.1 15.8 10.8 2013.3340 MAY 136.8 79.1 34.9 25.3 16.1 10.9 2013.4173 JUN 135.9 77.3 33.9 25.8 16.3 11.1 2013.5007 JUL 132.9 75.6 35.4 25.0 16.3 11.4 2013.5840 AUG 129.3 74.2 34.8 24.9 16.2 11.6 2013.6673 SEP 125.3 73.1 33.1 24.1 16.2 11.7 2013.7507 OCT 121.0 71.9 31.9 22.2 16.1 11.7 2013.8340 NOV 117.5 70.5 31.3 22.5 16.2 11.9 2013.9173 DEC 115.3 68.8 30.2 23.2 16.3 11.7 2014.0007 JAN 111.4 66.9 28.4 23.3 16.3 10.9 2014.0840 FEB 104.9 64.9 27.0 22.8 16.1 10.6 2014.1673 MAR 98.0 62.6 26.2 22.1 15.9 10.7 2014.2507 APR 94.1 60.4 26.3 22.0 15.9 10.7 2014.3340 MAY 93.1 58.6 25.8 22.9 16.1 10.6 2014.4173 JUN 92.2 57.1 24.2 23.8 16.4 10.7 2014.5007 JUL 89.9 55.6 24.3 24.0 16.6 10.7 2014.5840 AUG 87.6 54.1 23.9 24.0 16.8 10.6 2014.6673 SEP 83.8 52.4 22.9 24.0 16.9 10.5 2014.7507 OCT 80.3 50.7 22.1 23.6 16.9 10.2 2014.8340 NOV 76.6 49.0 20.9 22.7 16.9 10.3 2014.9173 DEC 71.1 47.1 19.3 22.9 16.8 10.5 2015.0007 JAN 69.8 45.4 16.8 23.1 16.9 11.3 2015.0840 FEB 70.3 44.2 14.9 23.2 17.2 11.8 2015.1673 MAR 69.9 42.9 13.8 22.6 17.3 11.9 2015.2507 APR 69.7 41.8 12.3 21.6 17.2 12.1 2015.3340 MAY 68.9 40.4 10.5 21.3 17.1 12.2 2015.4173 JUN 66.9 38.9 9.5 21.8 16.9 12.4 2015.5007 JUL 64.3 37.4 8.7 21.8 16.7 13.2 2015.5840 AUG 61.0 36.1 7.8 22.2 16.8 13.0 2015.6673 SEP 56.5 34.7 7.6 22.6 16.9 12.7 2015.7507 OCT 52.1 33.2 7.7 22.4 16.9 13.0 2015.8340 NOV 48.9 32.1 7.4 22.4 16.7 12.7 2015.9173 DEC 49.9 31.3 7.2 22.8 16.5 12.4 2016.0007 JAN 49.1 30.3 7.3 23.0 16.1 12.0 2016.0840 FEB 46.6 29.0 7.2 23.6 15.8 11.1 2016.1673 MAR 44.5 27.6 7.7 24.2 15.6 10.4 2016.2507 APR 42.4 26.3 6.6 25.0 15.5 10.5 2016.3340 MAY 41.1 25.4 6.2 25.5 15.5 10.6 2016.4173 JUN 39.5 24.4 5.8 25.7 15.5 10.5 2016.5007 JUL 38.9 23.5 5.4 25.6 15.4 10.6 2016.5840 AUG 38.3 22.5 4.9 25.0 15.3 10.9 2016.6673 SEP 37.9 21.6 4.3 24.1 15.1 11.0 2016.7507 OCT 37.1 20.6 3.5 23.1 14.9 11.2 2016.8340 NOV 36.1 19.7 3.4 22.6 15.0 11.1 2016.9173 DEC 34.9 19.0 3.3 22.2 15.2 11.0 2017.0007 JAN 33.5 18.1 3.1 21.9 15.4 11.1 2017.0840 FEB 31.8 17.1 2.5 21.5 15.5 11.3 2017.1673 MAR 29.9 16.2 1.9 20.8 15.5 11.4 2017.2507 APR 27.1 15.3 1.4 20.0 15.3 11.4 2017.3340 MAY 24.6 14.3 1.4 20.1 15.1 11.7 2017.4173 JUN 22.2 13.1 1.2 20.2 14.9 11.9 2017.5007 JUL 20.3 12.0 0.8 19.9 14.7 11.6 2017.5840 AUG 19.2 11.1 0.5 19.5 14.6 11.5 2017.6673 SEP 19.0 10.3 0.4 19.0 14.6 11.1 2017.7507 OCT 18.6 9.5 0.4 18.2 14.6 10.6 2017.8340 NOV 18.2 8.8 0.3 17.3 14.5 9.8 2017.9173 DEC 16.8 8.3 0.2 17.4 14.4 9.4 2018.0007 JAN 15.9 7.8 0.1 17.5 14.3 9.3 2018.0840 FEB 15.9 7.3 0.0 17.6 14.2 9.3 2018.1673 MAR 15.1 6.8 0.0 17.6 14.1 9.3