Annual Number of Years
1960-01-01 69.2744836840140
1961-01-01 69.6452667548157
1962-01-01 69.6038869024486
1963-01-01 69.7735332814793
1964-01-01 70.2334968620701
1965-01-01 70.3197947641960
1966-01-01 70.5967025836067
1967-01-01 70.7368900533402
1968-01-01 70.7871373880975
1969-01-01 70.7939165716523
1970-01-01 71.1583122930886
1971-01-01 71.2662748128238
1972-01-01 71.6058064755353
1973-01-01 71.7010345844960
1974-01-01 72.0268567829313
1975-01-01 72.1702768358900
1976-01-01 72.4357780430856
1977-01-01 72.7910814634574
1978-01-01 73.0122015847906
1979-01-01 73.3353892092198
1980-01-01 73.5296239919765
1981-01-01 73.8123426541960
1982-01-01 74.1552106037526
1983-01-01 74.2297241829691
1984-01-01 74.5878752489138
1985-01-01 74.7575598993759
1986-01-01 75.0569204700292
1987-01-01 75.3480820867599
1988-01-01 75.5356923844060
1989-01-01 75.7615255159746
1990-01-01 75.9114532653494
1991-01-01 76.0250664980680
1992-01-01 76.3800851083396
1993-01-01 76.4867305900405
1994-01-01 76.7950188371911
1995-01-01 76.9556835588635
1996-01-01 77.2182105146185
1997-01-01 77.5813573399368
1998-01-01 77.7969376438583
1999-01-01 78.0209973756490
2000-01-01 78.2748926912842
2001-01-01 78.5971155115040
2002-01-01 78.6844678776239
2003-01-01 78.7071825494894
2004-01-01 79.2787016221772
2005-01-01 79.4262861302399
2006-01-01 79.8561324119991
2007-01-01 80.0998851001265
2008-01-01 80.3029158374912
2009-01-01 80.5051815800699
2010-01-01 80.7467810041428
2011-01-01 81.2328031748937
2012-01-01 81.2270979386238
2013-01-01 81.5129528903896
2014-01-01 81.9332888456329
2015-01-01 81.5596100692018
2016-01-01 81.5599298047669