Year	Number of Years
1960-01-01	68.7315746449879
1961-01-01	69.1195352589115
1962-01-01	69.0922352231103
1963-01-01	69.3023088416881
1964-01-01	69.7089669386968
1965-01-01	69.8189465301930
1966-01-01	70.0887363145696
1967-01-01	70.3233004320784
1968-01-01	70.2608577644343
1969-01-01	70.4534007850313
1970-01-01	70.7838854264069
1971-01-01	71.0607353169745
1972-01-01	71.3515945376537
1973-01-01	71.5159862519522
1974-01-01	71.9345422021328
1975-01-01	72.2806813647022
1976-01-01	72.5406203354357
1977-01-01	72.8976746040505
1978-01-01	73.0462492361571
1979-01-01	73.3795064464307
1980-01-01	73.3897314152082
1981-01-01	73.7561683932045
1982-01-01	74.0889414986784
1983-01-01	74.1906476488570
1984-01-01	74.4747982165398
1985-01-01	74.5864904782937
1986-01-01	74.8294209399779
1987-01-01	75.1114183450662
1988-01-01	75.2276620814369
1989-01-01	75.4861523777353
1990-01-01	75.6422658240222
1991-01-01	75.8162239133647
1992-01-01	76.0815123871991
1993-01-01	76.1665650819835
1994-01-01	76.4601875232193
1995-01-01	76.5223718651038
1996-01-01	76.8898832946352
1997-01-01	77.2197395437167
1998-01-01	77.4028661081876
1999-01-01	77.5544101197518
2000-01-01	77.8256298944942
2001-01-01	78.1297402700414
2002-01-01	78.2678691245478
2003-01-01	78.3949642616987
2004-01-01	78.8413686715954
2005-01-01	78.9534986209733
2006-01-01	79.2753060709489
2007-01-01	79.5191236760607
2008-01-01	79.6751408440244
2009-01-01	79.9608835544481
2010-01-01	80.1525899380953
2011-01-01	80.4249565256317
2012-01-01	80.5459358805724
2013-01-01	80.7581545199533
2014-01-01	80.8846106047664