Year	Number of Years
1960-01-01	38.419
1961-01-01	39.082
1962-01-01	39.711
1963-01-01	40.290
1964-01-01	40.810
1965-01-01	41.267
1966-01-01	41.668
1967-01-01	42.026
1968-01-01	42.355
1969-01-01	42.659
1970-01-01	42.944
1971-01-01	43.213
1972-01-01	43.465
1973-01-01	43.693
1974-01-01	43.894
1975-01-01	44.045
1976-01-01	44.116
1977-01-01	44.103
1978-01-01	44.016
1979-01-01	43.880
1980-01-01	43.746
1981-01-01	43.674
1982-01-01	43.711
1983-01-01	43.884
1984-01-01	44.198
1985-01-01	44.633
1986-01-01	45.146
1987-01-01	45.682
1988-01-01	46.194
1989-01-01	46.668
1990-01-01	47.100
1991-01-01	47.505
1992-01-01	47.912
1993-01-01	48.346
1994-01-01	48.812
1995-01-01	49.305
1996-01-01	49.811
1997-01-01	50.322
1998-01-01	50.836
1999-01-01	51.366
2000-01-01	51.940
2001-01-01	52.593
2002-01-01	53.347
2003-01-01	54.209
2004-01-01	55.172
2005-01-01	56.221
2006-01-01	57.333
2007-01-01	58.466
2008-01-01	59.580
2009-01-01	60.643
2010-01-01	61.625
2011-01-01	62.501
2012-01-01	63.275
2013-01-01	63.952
2014-01-01	64.535
2015-01-01	65.037
2016-01-01	65.475