Year	Number of Years
1960-01-01	45.369
1961-01-01	46.093
1962-01-01	46.830
1963-01-01	47.573
1964-01-01	48.312
1965-01-01	49.035
1966-01-01	49.733
1967-01-01	50.406
1968-01-01	51.053
1969-01-01	51.678
1970-01-01	52.286
1971-01-01	52.887
1972-01-01	53.492
1973-01-01	54.109
1974-01-01	54.741
1975-01-01	55.387
1976-01-01	56.046
1977-01-01	56.709
1978-01-01	57.370
1979-01-01	58.023
1980-01-01	58.667
1981-01-01	59.297
1982-01-01	59.915
1983-01-01	60.520
1984-01-01	61.111
1985-01-01	61.682
1986-01-01	62.231
1987-01-01	62.758
1988-01-01	63.266
1989-01-01	63.763
1990-01-01	64.256
1991-01-01	64.757
1992-01-01	65.275
1993-01-01	65.815
1994-01-01	66.377
1995-01-01	66.963
1996-01-01	67.570
1997-01-01	68.189
1998-01-01	68.807
1999-01-01	69.417
2000-01-01	70.008
2001-01-01	70.571
2002-01-01	71.102
2003-01-01	71.600
2004-01-01	72.060
2005-01-01	72.481
2006-01-01	72.866
2007-01-01	73.219
2008-01-01	73.549
2009-01-01	73.859
2010-01-01	74.154
2011-01-01	74.437
2012-01-01	74.711
2013-01-01	74.977
2014-01-01	75.239
2015-01-01	75.498
2016-01-01	75.755