Year	Percent of Total
1960-01-01	64.9364626303222
1961-01-01	64.7309339477212
1962-01-01	64.5309072410367
1963-01-01	64.2896233349058
1964-01-01	64.0112660467722
1965-01-01	63.7272677621789
1966-01-01	63.5084038510851
1967-01-01	63.2928716287400
1968-01-01	63.1009642783869
1969-01-01	62.9426800807215
1970-01-01	62.8210981387371
1971-01-01	62.8860678514772
1972-01-01	62.9630219238938
1973-01-01	63.0803115859798
1974-01-01	63.2741670699942
1975-01-01	63.5545836411405
1976-01-01	63.7832905603625
1977-01-01	64.1265724962747
1978-01-01	64.5362533500523
1979-01-01	64.9478029916809
1980-01-01	65.3260692459016
1981-01-01	65.7340468071046
1982-01-01	66.0886171509727
1983-01-01	66.3843179842004
1984-01-01	66.6270173466483
1985-01-01	66.8115784994144
1986-01-01	66.8162933465700
1987-01-01	66.7935461033576
1988-01-01	66.7387091395630
1989-01-01	66.6528447489068
1990-01-01	66.5564223705734
1991-01-01	66.3602755734826
1992-01-01	66.1820178411648
1993-01-01	66.0414907780563
1994-01-01	65.9615678678832
1995-01-01	65.9514884732320
1996-01-01	65.8565464537585
1997-01-01	65.8117647847540
1998-01-01	65.8277763447950
1999-01-01	65.9082653241067
2000-01-01	66.0519698957832
2001-01-01	66.3081162949168
2002-01-01	66.5514286361232
2003-01-01	66.7879000173386
2004-01-01	67.0191634837944
2005-01-01	67.2414638609770
2006-01-01	67.3833138953607
2007-01-01	67.5440041397618
2008-01-01	67.7125215460456
2009-01-01	67.8605781671891
2010-01-01	67.9635687653799
2011-01-01	67.7933011048154
2012-01-01	67.5910347729489
2013-01-01	67.3495513012564
2014-01-01	67.0619606826283
2015-01-01	66.7187029959146
2016-01-01	66.4645633850471
2017-01-01	66.1744104498603