Year	Number of Years
1960-01-01	71.2365853658537
1961-01-01	70.9853658536586
1962-01-01	71.2317073170732
1963-01-01	71.2804878048780
1964-01-01	71.3292682926829
1965-01-01	71.2268292682927
1966-01-01	71.1243902439025
1967-01-01	71.4731707317073
1968-01-01	71.1243902439025
1969-01-01	71.4731707317073
1970-01-01	71.2731707317073
1971-01-01	71.7731707317073
1972-01-01	71.8292682926829
1973-01-01	71.6682926829268
1974-01-01	71.9243902439024
1975-01-01	72.2195121951220
1976-01-01	72.4219512195122
1977-01-01	72.1682926829268
1978-01-01	73.0195121951220
1979-01-01	73.0682926829269
1980-01-01	72.8292682926829
1981-01-01	73.6219512195122
1982-01-01	73.7243902439024
1983-01-01	73.7756097560976
1984-01-01	74.3707317073171
1985-01-01	73.8292682926829
1986-01-01	74.1219512195122
1987-01-01	74.1780487804878
1988-01-01	74.4243902439024
1989-01-01	74.8243902439024
1990-01-01	75.3780487804878
1991-01-01	76.0317073170732
1992-01-01	76.1243902439025
1993-01-01	76.4341463414634
1994-01-01	76.8829268292683
1995-01-01	76.7341463414634
1996-01-01	76.7878048780488
1997-01-01	77.3341463414634
1998-01-01	78.0853658536585
1999-01-01	77.8902439024390
2000-01-01	78.6365853658537
2001-01-01	78.6926829268293
2002-01-01	78.8463414634146
2003-01-01	79.1463414634146
2004-01-01	79.5487804878049
2005-01-01	79.8512195121951
2006-01-01	80.0487804878049
2007-01-01	80.1512195121951
2008-01-01	80.3512195121951
2009-01-01	80.7024390243902
2010-01-01	80.7024390243902
2011-01-01	80.9048780487805
2012-01-01	81.1560975609756
2013-01-01	81.4073170731707
2014-01-01	81.4048780487805
2015-01-01	81.4568292682927
2016-01-01	81.6124390243903