Year	Number of Years
1960-01-01	35.026
1961-01-01	35.490
1962-01-01	35.936
1963-01-01	36.363
1964-01-01	36.773
1965-01-01	37.174
1966-01-01	37.573
1967-01-01	37.980
1968-01-01	38.397
1969-01-01	38.826
1970-01-01	39.271
1971-01-01	39.735
1972-01-01	40.210
1973-01-01	40.679
1974-01-01	41.125
1975-01-01	41.512
1976-01-01	41.804
1977-01-01	41.983
1978-01-01	42.050
1979-01-01	42.017
1980-01-01	41.913
1981-01-01	41.778
1982-01-01	41.660
1983-01-01	41.597
1984-01-01	41.610
1985-01-01	41.705
1986-01-01	41.872
1987-01-01	42.085
1988-01-01	42.327
1989-01-01	42.600
1990-01-01	42.915
1991-01-01	43.293
1992-01-01	43.745
1993-01-01	44.272
1994-01-01	44.862
1995-01-01	45.491
1996-01-01	46.124
1997-01-01	46.736
1998-01-01	47.309
1999-01-01	47.841
2000-01-01	48.348
2001-01-01	48.859
2002-01-01	49.406
2003-01-01	50.007
2004-01-01	50.663
2005-01-01	51.362
2006-01-01	52.079
2007-01-01	52.785
2008-01-01	53.459
2009-01-01	54.096
2010-01-01	54.700
2011-01-01	55.288
2012-01-01	55.878
2013-01-01	56.483
2014-01-01	57.099
2015-01-01	57.714
2016-01-01	58.311