Year	Percent of Total
1960-01-01	62.1470574460973
1961-01-01	61.9553098520482
1962-01-01	61.9875580049838
1963-01-01	62.1664303613360
1964-01-01	62.3535744402751
1965-01-01	62.4815812877262
1966-01-01	62.4536931132899
1967-01-01	62.4348702254692
1968-01-01	62.4176466630065
1969-01-01	62.4097592548419
1970-01-01	62.4165520657384
1971-01-01	62.4493856179424
1972-01-01	62.4793792837036
1973-01-01	62.5244630988774
1974-01-01	62.6196710349340
1975-01-01	62.7858548637229
1976-01-01	62.8472406010448
1977-01-01	62.9915610807513
1978-01-01	63.2259061878817
1979-01-01	63.5502243039132
1980-01-01	63.9579220709759
1981-01-01	64.4608420063743
1982-01-01	64.9976658955738
1983-01-01	65.5239813205309
1984-01-01	65.9812252903635
1985-01-01	66.3245524408492
1986-01-01	66.3580733719617
1987-01-01	66.3416446245275
1988-01-01	66.2819144542895
1989-01-01	66.1931700861815
1990-01-01	66.0978723363167
1991-01-01	65.9689097930591
1992-01-01	65.8274242397522
1993-01-01	65.6830534756191
1994-01-01	65.5534517876939
1995-01-01	65.4437893230309
1996-01-01	65.3673406708197
1997-01-01	65.2994691678383
1998-01-01	65.2490752041491
1999-01-01	65.2208429659755
2000-01-01	65.2126122712544
2001-01-01	65.1604910543348
2002-01-01	65.1358962170508
2003-01-01	65.1279171361195
2004-01-01	65.1271370730184
2005-01-01	65.1268806984367
2006-01-01	65.1051670189693
2007-01-01	65.0994005095145
2008-01-01	65.0728955007822
2009-01-01	64.9743878051901
2010-01-01	64.7731565998813
2011-01-01	64.4722131811407
2012-01-01	64.0818202135633
2013-01-01	63.6360479003751
2014-01-01	63.1941981944470
2015-01-01	62.7964205271650
2016-01-01	62.4795270260561
2017-01-01	62.1982212003075