Year	Number of Years
1960-01-01	45.844
1961-01-01	46.280
1962-01-01	46.697
1963-01-01	47.094
1964-01-01	47.470
1965-01-01	47.824
1966-01-01	48.156
1967-01-01	48.469
1968-01-01	48.768
1969-01-01	49.056
1970-01-01	49.339
1971-01-01	49.623
1972-01-01	49.911
1973-01-01	50.204
1974-01-01	50.505
1975-01-01	50.809
1976-01-01	51.110
1977-01-01	51.405
1978-01-01	51.693
1979-01-01	51.977
1980-01-01	52.268
1981-01-01	52.575
1982-01-01	52.907
1983-01-01	53.272
1984-01-01	53.670
1985-01-01	54.111
1986-01-01	54.605
1987-01-01	55.140
1988-01-01	55.697
1989-01-01	56.251
1990-01-01	56.755
1991-01-01	57.160
1992-01-01	57.439
1993-01-01	57.583
1994-01-01	57.598
1995-01-01	57.507
1996-01-01	57.347
1997-01-01	57.171
1998-01-01	57.032
1999-01-01	56.962
2000-01-01	56.994
2001-01-01	57.147
2002-01-01	57.410
2003-01-01	57.761
2004-01-01	58.187
2005-01-01	58.666
2006-01-01	59.167
2007-01-01	59.663
2008-01-01	60.128
2009-01-01	60.550
2010-01-01	60.924
2011-01-01	61.254
2012-01-01	61.561
2013-01-01	61.860
2014-01-01	62.154
2015-01-01	62.448
2016-01-01	62.742