Year	Number of Years
1960-01-01	43.488
1961-01-01	44.171
1962-01-01	44.835
1963-01-01	45.472
1964-01-01	46.077
1965-01-01	46.648
1966-01-01	47.184
1967-01-01	47.694
1968-01-01	48.185
1969-01-01	48.662
1970-01-01	49.130
1971-01-01	49.590
1972-01-01	50.046
1973-01-01	50.504
1974-01-01	50.969
1975-01-01	51.453
1976-01-01	51.966
1977-01-01	52.511
1978-01-01	53.084
1979-01-01	53.678
1980-01-01	54.280
1981-01-01	54.876
1982-01-01	55.450
1983-01-01	55.986
1984-01-01	56.476
1985-01-01	56.912
1986-01-01	57.293
1987-01-01	57.625
1988-01-01	57.919
1989-01-01	58.180
1990-01-01	58.415
1991-01-01	58.633
1992-01-01	58.839
1993-01-01	59.039
1994-01-01	59.233
1995-01-01	59.419
1996-01-01	59.587
1997-01-01	59.733
1998-01-01	59.855
1999-01-01	59.957
2000-01-01	60.049
2001-01-01	60.143
2002-01-01	60.250
2003-01-01	60.381
2004-01-01	60.539
2005-01-01	60.729
2006-01-01	60.952
2007-01-01	61.199
2008-01-01	61.461
2009-01-01	61.730
2010-01-01	61.997
2011-01-01	62.253
2012-01-01	62.492
2013-01-01	62.711
2014-01-01	62.907
2015-01-01	63.082
2016-01-01	63.238