Year	Number of Years
1960-01-01	42.113
1961-01-01	42.697
1962-01-01	43.277
1963-01-01	43.849
1964-01-01	44.412
1965-01-01	44.955
1966-01-01	45.472
1967-01-01	45.955
1968-01-01	46.405
1969-01-01	46.823
1970-01-01	47.215
1971-01-01	47.592
1972-01-01	47.965
1973-01-01	48.341
1974-01-01	48.723
1975-01-01	49.107
1976-01-01	49.485
1977-01-01	49.849
1978-01-01	50.196
1979-01-01	50.527
1980-01-01	50.852
1981-01-01	51.182
1982-01-01	51.527
1983-01-01	51.892
1984-01-01	52.279
1985-01-01	52.680
1986-01-01	53.088
1987-01-01	53.492
1988-01-01	53.881
1989-01-01	54.253
1990-01-01	54.609
1991-01-01	54.954
1992-01-01	55.296
1993-01-01	55.639
1994-01-01	55.981
1995-01-01	56.316
1996-01-01	56.635
1997-01-01	56.933
1998-01-01	57.209
1999-01-01	57.467
2000-01-01	57.716
2001-01-01	57.969
2002-01-01	58.239
2003-01-01	58.535
2004-01-01	58.860
2005-01-01	59.219
2006-01-01	59.610
2007-01-01	60.023
2008-01-01	60.448
2009-01-01	60.876
2010-01-01	61.296
2011-01-01	61.699
2012-01-01	62.078
2013-01-01	62.432
2014-01-01	62.757
2015-01-01	63.055
2016-01-01	63.330