Year	Number of Years
1960-01-01	62.115
1961-01-01	62.555
1962-01-01	62.979
1963-01-01	63.385
1964-01-01	63.774
1965-01-01	64.148
1966-01-01	64.510
1967-01-01	64.864
1968-01-01	65.212
1969-01-01	65.557
1970-01-01	65.897
1971-01-01	66.232
1972-01-01	66.558
1973-01-01	66.875
1974-01-01	67.181
1975-01-01	67.479
1976-01-01	67.768
1977-01-01	68.051
1978-01-01	68.328
1979-01-01	68.602
1980-01-01	68.873
1981-01-01	69.141
1982-01-01	69.408
1983-01-01	69.671
1984-01-01	69.931
1985-01-01	70.187
1986-01-01	70.435
1987-01-01	70.675
1988-01-01	70.907
1989-01-01	71.132
1990-01-01	71.351
1991-01-01	71.567
1992-01-01	71.783
1993-01-01	71.999
1994-01-01	72.218
1995-01-01	72.440
1996-01-01	72.663
1997-01-01	72.887
1998-01-01	73.108
1999-01-01	73.327
2000-01-01	73.541
2001-01-01	73.752
2002-01-01	73.957
2003-01-01	74.158
2004-01-01	74.354
2005-01-01	74.544
2006-01-01	74.727
2007-01-01	74.905
2008-01-01	75.078
2009-01-01	75.247
2010-01-01	75.412
2011-01-01	75.574
2012-01-01	75.733
2013-01-01	75.892
2014-01-01	76.050
2015-01-01	76.207
2016-01-01	76.364