Year	Number of Years
1960-01-01	67.0374456460047
1961-01-01	67.4005976377579
1962-01-01	67.4934192939521
1963-01-01	67.7620035001948
1964-01-01	68.1580799970085
1965-01-01	68.3084212633907
1966-01-01	68.5175324284995
1967-01-01	68.6405382502617
1968-01-01	68.7097583717102
1969-01-01	68.7156212172011
1970-01-01	68.9930416292631
1971-01-01	69.1296280236473
1972-01-01	69.3337813198581
1973-01-01	69.4290308953883
1974-01-01	69.6327499413669
1975-01-01	69.6073868567392
1976-01-01	69.7082024689227
1977-01-01	69.8806867259641
1978-01-01	69.9700990595614
1979-01-01	70.0890978259054
1980-01-01	70.1934279521688
1981-01-01	70.4584916655522
1982-01-01	70.7495508355080
1983-01-01	70.8190152041582
1984-01-01	70.9693904167093
1985-01-01	71.1819401235027
1986-01-01	71.6669562406911
1987-01-01	71.8838535317716
1988-01-01	72.0114845907485
1989-01-01	72.0741689644662
1990-01-01	72.0771679099716
1991-01-01	71.9863856398820
1992-01-01	71.9162978905402
1993-01-01	71.5985239333488
1994-01-01	71.6666366045067
1995-01-01	71.7656136987534
1996-01-01	72.1519851487876
1997-01-01	72.5588883093229
1998-01-01	72.8664639502896
1999-01-01	72.9164644465100
2000-01-01	73.0708005190979
2001-01-01	73.3465694356180
2002-01-01	73.4337937270446
2003-01-01	73.5451141743090
2004-01-01	73.9782434688798
2005-01-01	74.1398942484846
2006-01-01	74.6343390267460
2007-01-01	74.9905084966995
2008-01-01	75.2474934805903
2009-01-01	75.6407690582016
2010-01-01	75.9292326451287
2011-01-01	76.4417573702601
2012-01-01	76.5884049599590
2013-01-01	76.9014526017130
2014-01-01	77.2175838243798
2015-01-01	77.1566342219048
2016-01-01	77.2814460415160