Year	Number of Years
1960-01-01	45.265
1961-01-01	46.195
1962-01-01	47.085
1963-01-01	47.936
1964-01-01	48.747
1965-01-01	49.520
1966-01-01	50.255
1967-01-01	50.954
1968-01-01	51.617
1969-01-01	52.245
1970-01-01	52.837
1971-01-01	53.389
1972-01-01	53.901
1973-01-01	54.376
1974-01-01	54.815
1975-01-01	55.224
1976-01-01	55.606
1977-01-01	55.966
1978-01-01	56.311
1979-01-01	56.645
1980-01-01	56.972
1981-01-01	57.295
1982-01-01	57.613
1983-01-01	57.926
1984-01-01	58.237
1985-01-01	58.545
1986-01-01	58.852
1987-01-01	59.157
1988-01-01	59.458
1989-01-01	59.756
1990-01-01	60.050
1991-01-01	60.338
1992-01-01	60.621
1993-01-01	60.898
1994-01-01	61.169
1995-01-01	61.436
1996-01-01	61.700
1997-01-01	61.961
1998-01-01	62.220
1999-01-01	62.476
2000-01-01	62.727
2001-01-01	62.967
2002-01-01	63.196
2003-01-01	63.414
2004-01-01	63.625
2005-01-01	63.836
2006-01-01	64.060
2007-01-01	64.303
2008-01-01	64.565
2009-01-01	64.845
2010-01-01	65.134
2011-01-01	65.419
2012-01-01	65.686
2013-01-01	65.927
2014-01-01	66.139
2015-01-01	66.322
2016-01-01	66.481