Annual Number of Years
1960-01-01 49.5143922669332
1961-01-01 50.0373561898401
1962-01-01 50.7005485471229
1963-01-01 51.5602932075425
1964-01-01 52.6536416875966
1965-01-01 53.9196736377547
1966-01-01 55.2691180296231
1967-01-01 56.6210433224308
1968-01-01 57.8950324292340
1969-01-01 59.0256575677309
1970-01-01 60.0376965012218
1971-01-01 60.8943932876126
1972-01-01 61.6193183774928
1973-01-01 62.2999056657118
1974-01-01 62.9301480570822
1975-01-01 63.4551441201060
1976-01-01 63.9673799356125
1977-01-01 64.4337062736107
1978-01-01 64.8623032917998
1979-01-01 65.2228270469042
1980-01-01 65.5838188428859
1981-01-01 65.9343907420942
1982-01-01 66.2877036278956
1983-01-01 66.5833993856087
1984-01-01 66.8471966831222
1985-01-01 67.1872087599625
1986-01-01 67.5900054826482
1987-01-01 67.8539782692374
1988-01-01 68.1033426506424
1989-01-01 68.3112798343437
1990-01-01 68.5073333087745
1991-01-01 68.6906307139762
1992-01-01 68.7649053532548
1993-01-01 68.8195126569228
1994-01-01 68.9959557320353
1995-01-01 69.2394471637589
1996-01-01 69.5696541904713
1997-01-01 69.9160977528952
1998-01-01 70.2462493941434
1999-01-01 70.5108919724169
2000-01-01 70.8273296477610
2001-01-01 71.1606423087190
2002-01-01 71.4749870541955
2003-01-01 71.7946541487519
2004-01-01 72.1303351392015
2005-01-01 72.4205288506414
2006-01-01 72.7681198235190
2007-01-01 73.0834081711375
2008-01-01 73.3561712354907
2009-01-01 73.6538065259833
2010-01-01 73.8936137851468
2011-01-01 74.1790198545248
2012-01-01 74.4235102280132
2013-01-01 74.6679533053731
2014-01-01 74.8768031104745
2015-01-01 75.0888384917493
2016-01-01 75.2906209723914