Year	Number of Years
1960-01-01	35.045
1961-01-01	35.131
1962-01-01	35.212
1963-01-01	35.288
1964-01-01	35.359
1965-01-01	35.428
1966-01-01	35.496
1967-01-01	35.571
1968-01-01	35.657
1969-01-01	35.760
1970-01-01	35.884
1971-01-01	36.032
1972-01-01	36.204
1973-01-01	36.403
1974-01-01	36.634
1975-01-01	36.905
1976-01-01	37.227
1977-01-01	37.600
1978-01-01	38.020
1979-01-01	38.480
1980-01-01	38.962
1981-01-01	39.450
1982-01-01	39.927
1983-01-01	40.385
1984-01-01	40.821
1985-01-01	41.240
1986-01-01	41.654
1987-01-01	42.079
1988-01-01	42.531
1989-01-01	43.015
1990-01-01	43.540
1991-01-01	44.108
1992-01-01	44.711
1993-01-01	45.343
1994-01-01	45.996
1995-01-01	46.659
1996-01-01	47.323
1997-01-01	47.979
1998-01-01	48.622
1999-01-01	49.253
2000-01-01	49.874
2001-01-01	50.494
2002-01-01	51.123
2003-01-01	51.770
2004-01-01	52.436
2005-01-01	53.127
2006-01-01	53.849
2007-01-01	54.593
2008-01-01	55.350
2009-01-01	56.105
2010-01-01	56.838
2011-01-01	57.528
2012-01-01	58.160
2013-01-01	58.727
2014-01-01	59.228
2015-01-01	59.667
2016-01-01	60.058