Year	Percent of Total
1960-01-01	62.3427483961371
1961-01-01	62.0298931535969
1962-01-01	61.9502795377026
1963-01-01	62.0527360654347
1964-01-01	62.2280891895162
1965-01-01	62.4210630897566
1966-01-01	62.6437566451764
1967-01-01	62.9075513915156
1968-01-01	63.2007971181644
1969-01-01	63.5057665080298
1970-01-01	63.8007715294334
1971-01-01	64.1666308250211
1972-01-01	64.4584467964150
1973-01-01	64.6948280462975
1974-01-01	64.9078477708987
1975-01-01	65.1058350463480
1976-01-01	65.1044327684885
1977-01-01	65.1609044084452
1978-01-01	65.2338762681846
1979-01-01	65.2766500179278
1980-01-01	65.2700882265717
1981-01-01	65.2625973270665
1982-01-01	65.2079019038467
1983-01-01	65.1166275600838
1984-01-01	65.0280335645706
1985-01-01	64.9575442903942
1986-01-01	64.8040859285064
1987-01-01	64.6866428301820
1988-01-01	64.5932013586222
1989-01-01	64.5131147267154
1990-01-01	64.4490121284135
1991-01-01	64.2958039200582
1992-01-01	64.2046257189165
1993-01-01	64.2087074742935
1994-01-01	64.3039324832983
1995-01-01	64.5195067037842
1996-01-01	64.9190411364865
1997-01-01	65.3380322838052
1998-01-01	65.7698492430357
1999-01-01	66.2067564953911
2000-01-01	66.6395907141100
2001-01-01	66.9408534633552
2002-01-01	67.2543161253649
2003-01-01	67.5842818127023
2004-01-01	67.9447371280495
2005-01-01	68.3360897724526
2006-01-01	68.6977028834042
2007-01-01	69.0989850070548
2008-01-01	69.4680784331816
2009-01-01	69.7361836190782
2010-01-01	69.8791899921547
2011-01-01	69.8758015429933
2012-01-01	69.7639023934671
2013-01-01	69.5733443865719
2014-01-01	69.3461895274414