Year	Number of Years
1960-01-01	72.1765853658537
1961-01-01	72.4382926829268
1962-01-01	72.3197560975610
1963-01-01	72.4004878048781
1964-01-01	72.4851219512195
1965-01-01	72.3707317073171
1966-01-01	72.4441463414634
1967-01-01	72.9221951219512
1968-01-01	73.1214634146342
1969-01-01	73.2209756097561
1970-01-01	73.3434146341463
1971-01-01	73.4146341463415
1972-01-01	73.4390243902439
1973-01-01	73.6821951219512
1974-01-01	73.8082926829268
1975-01-01	74.0751219512195
1976-01-01	73.7397560975610
1977-01-01	74.6324390243903
1978-01-01	74.3929268292683
1979-01-01	74.2192682926829
1980-01-01	74.1017073170732
1981-01-01	74.2304878048781
1982-01-01	74.5512195121951
1983-01-01	74.4204878048781
1984-01-01	74.5621951219512
1985-01-01	74.4275609756098
1986-01-01	74.5797560975610
1987-01-01	74.6912195121951
1988-01-01	74.7717073170732
1989-01-01	74.7997560975610
1990-01-01	74.8053658536585
1991-01-01	75.1578048780488
1992-01-01	75.1941463414634
1993-01-01	75.1168292682927
1994-01-01	75.3751219512195
1995-01-01	75.2126829268293
1996-01-01	75.5914634146342
1997-01-01	75.9451219512195
1998-01-01	76.1390243902439
1999-01-01	76.3414634146341
2000-01-01	76.5926829268293
2001-01-01	76.7926829268293
2002-01-01	76.8951219512195
2003-01-01	77.1439024390244
2004-01-01	77.4926829268293
2005-01-01	77.8439024390244
2006-01-01	78.0951219512195
2007-01-01	78.1951219512195
2008-01-01	78.4463414634146
2009-01-01	78.5975609756098
2010-01-01	79.1000000000000
2011-01-01	79.8000000000000
2012-01-01	80.0512195121951
2013-01-01	80.3000000000000
2014-01-01	80.7000000000000
2015-01-01	80.7024390243902
2016-01-01	80.7048780487805