Year	Number of Years
1960-01-01	68.8197560975610
1961-01-01	68.8441463414634
1962-01-01	68.5778048780488
1963-01-01	69.0126829268293
1964-01-01	69.2209756097561
1965-01-01	68.9778048780488
1966-01-01	69.4770731707317
1967-01-01	69.6665853658537
1968-01-01	69.6163414634146
1969-01-01	69.5034146341464
1970-01-01	70.1795121951220
1971-01-01	70.0175609756098
1972-01-01	70.7073170731707
1973-01-01	71.2236585365854
1974-01-01	71.1348780487805
1975-01-01	71.6736585365854
1976-01-01	71.8129268292683
1977-01-01	72.3502439024390
1978-01-01	72.8970731707317
1979-01-01	73.1553658536586
1980-01-01	73.4400000000000
1981-01-01	73.7465853658537
1982-01-01	74.2980487804878
1983-01-01	74.2009756097561
1984-01-01	74.5190243902439
1985-01-01	74.2229268292683
1986-01-01	74.5600000000000
1987-01-01	74.5919512195122
1988-01-01	74.5770731707317
1989-01-01	74.7921951219512
1990-01-01	74.8131707317073
1991-01-01	75.2275609756098
1992-01-01	75.4553658536585
1993-01-01	75.7051219512195
1994-01-01	76.3956097560976
1995-01-01	76.4095121951220
1996-01-01	76.6934146341464
1997-01-01	76.8785365853659
1998-01-01	77.0907317073171
1999-01-01	77.2912195121951
2000-01-01	77.4658536585366
2001-01-01	77.9658536585366
2002-01-01	78.1195121951220
2003-01-01	78.3682926829268
2004-01-01	78.7146341463415
2005-01-01	78.8170731707317
2006-01-01	79.2146341463415
2007-01-01	79.2634146341464
2008-01-01	79.5682926829268
2009-01-01	79.7195121951220
2010-01-01	79.8707317073171
2011-01-01	80.4707317073171
2012-01-01	80.6268292682927
2013-01-01	80.9756097560976
2014-01-01	81.1804878048781
2015-01-01	81.4804878048781
2016-01-01	81.7804878048781