Year	Percent of Total
1960-01-01	64.5183150023524
1961-01-01	64.3362673148703
1962-01-01	64.2486407300372
1963-01-01	64.2215976962620
1964-01-01	64.1955355490065
1965-01-01	64.1419187553249
1966-01-01	64.0129876061446
1967-01-01	63.8852629996938
1968-01-01	63.7648948108760
1969-01-01	63.6713302101955
1970-01-01	63.6146722463543
1971-01-01	63.5511931486877
1972-01-01	63.5473815577735
1973-01-01	63.5913143716079
1974-01-01	63.6653212618724
1975-01-01	63.7607254488667
1976-01-01	63.8256941907718
1977-01-01	63.8971717714843
1978-01-01	64.0131744453244
1979-01-01	64.2297044064687
1980-01-01	64.5679370351781
1981-01-01	64.9116182506438
1982-01-01	65.3727500974909
1983-01-01	65.8783782834462
1984-01-01	66.3238486935282
1985-01-01	66.6508032782536
1986-01-01	66.8019512619761
1987-01-01	66.8592212510682
1988-01-01	66.8569262508015
1989-01-01	66.8532711840459
1990-01-01	66.8797102514420
1991-01-01	66.8450203019142
1992-01-01	66.8444493259038
1993-01-01	66.8686564018239
1994-01-01	66.9038978399075
1995-01-01	66.9464364127521
1996-01-01	66.9747536533785
1997-01-01	67.0148843511716
1998-01-01	67.0628770698866
1999-01-01	67.1138461426560
2000-01-01	67.1596078637365
2001-01-01	67.1825306947585
2002-01-01	67.2007322178854
2003-01-01	67.2158510411831
2004-01-01	67.2317923464359
2005-01-01	67.2489127382466
2006-01-01	67.1959002397763
2007-01-01	67.1507454470268
2008-01-01	67.0928326774213
2009-01-01	66.9974285438520
2010-01-01	66.8482108374588
2011-01-01	66.5940860071403
2012-01-01	66.3169212960732
2013-01-01	66.0148923417456
2014-01-01	65.6971142179298
2015-01-01	65.3761736776614
2016-01-01	65.1063200065011
2017-01-01	64.8213893784669