Year	Number of Years
1960-01-01	65.022
1961-01-01	65.141
1962-01-01	65.233
1963-01-01	65.311
1964-01-01	65.388
1965-01-01	65.481
1966-01-01	65.603
1967-01-01	65.760
1968-01-01	65.953
1969-01-01	66.184
1970-01-01	66.449
1971-01-01	66.740
1972-01-01	67.044
1973-01-01	67.349
1974-01-01	67.652
1975-01-01	67.950
1976-01-01	68.248
1977-01-01	68.549
1978-01-01	68.856
1979-01-01	69.164
1980-01-01	69.464
1981-01-01	69.746
1982-01-01	70.003
1983-01-01	70.234
1984-01-01	70.438
1985-01-01	70.623
1986-01-01	70.797
1987-01-01	70.971
1988-01-01	71.155
1989-01-01	71.352
1990-01-01	71.565
1991-01-01	71.790
1992-01-01	72.023
1993-01-01	72.256
1994-01-01	72.489
1995-01-01	72.719
1996-01-01	72.947
1997-01-01	73.173
1998-01-01	73.397
1999-01-01	73.618
2000-01-01	73.832
2001-01-01	74.039
2002-01-01	74.236
2003-01-01	74.424
2004-01-01	74.603
2005-01-01	74.775
2006-01-01	74.941
2007-01-01	75.105
2008-01-01	75.268
2009-01-01	75.431
2010-01-01	75.595
2011-01-01	75.761
2012-01-01	75.926
2013-01-01	76.089
2014-01-01	76.252
2015-01-01	76.415
2016-01-01	76.577