Year	Number of Years
1960-01-01	68.0031707317073
1961-01-01	68.9360975609756
1962-01-01	67.8658536585366
1963-01-01	68.8741463414634
1964-01-01	69.3809756097561
1965-01-01	69.0712195121951
1966-01-01	69.8224390243902
1967-01-01	69.4070731707317
1968-01-01	69.2302439024390
1969-01-01	69.3146341463415
1970-01-01	69.1646341463415
1971-01-01	69.0524390243903
1972-01-01	69.6646341463415
1973-01-01	69.5180487804878
1974-01-01	69.2480487804878
1975-01-01	69.2900000000000
1976-01-01	69.5731707317073
1977-01-01	69.8480487804878
1978-01-01	69.3939024390244
1979-01-01	69.6153658536585
1980-01-01	69.0617073170732
1981-01-01	69.1392682926829
1982-01-01	69.3578048780488
1983-01-01	68.9736585365854
1984-01-01	69.0258536585366
1985-01-01	68.9721951219512
1986-01-01	69.1734146341463
1987-01-01	69.6512195121951
1988-01-01	70.0234146341463
1989-01-01	69.4617073170732
1990-01-01	69.3156097560976
1991-01-01	69.3770731707317
1992-01-01	69.1170731707317
1993-01-01	69.1012195121951
1994-01-01	69.4697560975610
1995-01-01	69.7917073170732
1996-01-01	70.3287804878049
1997-01-01	70.7024390243902
1998-01-01	70.5578048780488
1999-01-01	70.6770731707317
2000-01-01	71.2463414634146
2001-01-01	72.2487804878049
2002-01-01	72.3487804878049
2003-01-01	72.3000000000000
2004-01-01	72.6487804878049
2005-01-01	72.6487804878049
2006-01-01	73.0975609756098
2007-01-01	73.1512195121951
2008-01-01	73.7024390243903
2009-01-01	73.9048780487805
2010-01-01	74.2073170731707
2011-01-01	74.8585365853659
2012-01-01	75.0634146341463
2013-01-01	75.5658536585366
2014-01-01	75.7634146341463
2015-01-01	75.5682926829269
2016-01-01	75.5682926829269