Year	Percent of Total
1960-01-01	62.4012607713079
1961-01-01	62.3066497207700
1962-01-01	62.3218643339314
1963-01-01	62.4170196844370
1964-01-01	62.5343333129506
1965-01-01	62.6441817992610
1966-01-01	62.6703795689714
1967-01-01	62.7166395623366
1968-01-01	62.7750200809665
1969-01-01	62.8640620921013
1970-01-01	62.9641646262344
1971-01-01	63.1032121790491
1972-01-01	63.2467426387249
1973-01-01	63.3989411841832
1974-01-01	63.5869120682970
1975-01-01	63.8101523504960
1976-01-01	63.9405446343652
1977-01-01	64.1239290931375
1978-01-01	64.3498910352443
1979-01-01	64.6058895336222
1980-01-01	64.8820668493118
1981-01-01	65.1686824380115
1982-01-01	65.4680280739733
1983-01-01	65.7589932905396
1984-01-01	66.0216943396508
1985-01-01	66.2432658071935
1986-01-01	66.3348989365912
1987-01-01	66.4120037032917
1988-01-01	66.4746911902048
1989-01-01	66.5244562277113
1990-01-01	66.5626143655551
1991-01-01	66.5515770045156
1992-01-01	66.5344342902868
1993-01-01	66.5191724857617
1994-01-01	66.5290528885028
1995-01-01	66.5753381075059
1996-01-01	66.5915771156079
1997-01-01	66.6540047097687
1998-01-01	66.7412765387314
1999-01-01	66.8234750692600
2000-01-01	66.8871426075899
2001-01-01	66.9733096446647
2002-01-01	67.0337288350406
2003-01-01	67.0804947295369
2004-01-01	67.1345293702490
2005-01-01	67.1997685475225
2006-01-01	67.2122980838152
2007-01-01	67.2414979775675
2008-01-01	67.2630485708676
2009-01-01	67.2422528641594
2010-01-01	67.1629866483795
2011-01-01	67.0131530694031
2012-01-01	66.8374720557852
2013-01-01	66.6307313361857
2014-01-01	66.3991756398984
2015-01-01	66.1501488066793
2016-01-01	65.9158790307045
2017-01-01	65.6567888718576