Year	Percent of Total
1960-01-01	63.0346570153247
1961-01-01	62.9268935678591
1962-01-01	62.9816636028149
1963-01-01	63.1263612547527
1964-01-01	63.2415689958998
1965-01-01	63.2642074844078
1966-01-01	63.2237381477865
1967-01-01	63.0939573057766
1968-01-01	62.9118283526447
1969-01-01	62.7528220178754
1970-01-01	62.6558412408477
1971-01-01	62.5088310177865
1972-01-01	62.4568824714488
1973-01-01	62.4671720525288
1974-01-01	62.4957065699954
1975-01-01	62.5281091887762
1976-01-01	62.5854164209585
1977-01-01	62.6610835416497
1978-01-01	62.7644774822914
1979-01-01	62.9089378786644
1980-01-01	63.0942498377416
1981-01-01	63.3374506248272
1982-01-01	63.5804980814304
1983-01-01	63.8258879378168
1984-01-01	64.0675036029566
1985-01-01	64.2905970352303
1986-01-01	64.4008786080806
1987-01-01	64.5131751663734
1988-01-01	64.6120772255410
1989-01-01	64.6818998599662
1990-01-01	64.7187556285957
1991-01-01	64.6829080230314
1992-01-01	64.6416006027000
1993-01-01	64.5935589146375
1994-01-01	64.5525225060260
1995-01-01	64.5314226373055
1996-01-01	64.5119091761853
1997-01-01	64.5237092280955
1998-01-01	64.5671284856209
1999-01-01	64.6452484173014
2000-01-01	64.7600651380516
2001-01-01	64.8879043232087
2002-01-01	65.0521258270148
2003-01-01	65.2391432496314
2004-01-01	65.4210308611126
2005-01-01	65.5727831405304
2006-01-01	65.7857468430818
2007-01-01	65.9679493046939
2008-01-01	66.1196724070395
2009-01-01	66.2355246748619
2010-01-01	66.3011028928680
2011-01-01	66.2151206798455
2012-01-01	66.1212963190195
2013-01-01	66.0103669397162
2014-01-01	65.8787182331964
2015-01-01	65.7346500928106
2016-01-01	65.5807169741949
2017-01-01	65.4047973539328