Year	Percent of Total
1960-01-01	57.0618251400975
1961-01-01	56.8234709765993
1962-01-01	56.7409734498744
1963-01-01	56.7847241623864
1964-01-01	56.8977173097846
1965-01-01	57.0601051410981
1966-01-01	57.2490896969075
1967-01-01	57.5052811282618
1968-01-01	57.8246998782986
1969-01-01	58.1931337696931
1970-01-01	58.5908837427724
1971-01-01	59.0415668701228
1972-01-01	59.4577214200992
1973-01-01	59.8663621754208
1974-01-01	60.3048760687131
1975-01-01	60.7864447195855
1976-01-01	61.1128007953117
1977-01-01	61.5055834000702
1978-01-01	61.9321882667856
1979-01-01	62.3198276891505
1980-01-01	62.6254041408557
1981-01-01	62.9235598099400
1982-01-01	63.1459816778054
1983-01-01	63.3114283172118
1984-01-01	63.4706542494389
1985-01-01	63.6421587701070
1986-01-01	63.7847837564615
1987-01-01	63.9527070785571
1988-01-01	64.1317926296065
1989-01-01	64.2835353171192
1990-01-01	64.3891422230761
1991-01-01	64.4140297487812
1992-01-01	64.3806866012431
1993-01-01	64.3248202972710
1994-01-01	64.3031176217668
1995-01-01	64.3398136973198
1996-01-01	64.3790486766611
1997-01-01	64.5442577986059
1998-01-01	64.7764587934441
1999-01-01	65.0005398207795
2000-01-01	65.1862285378073
2001-01-01	65.4473024704232
2002-01-01	65.6004121557921
2003-01-01	65.7099099849975
2004-01-01	65.8431350994833
2005-01-01	66.0114787832354
2006-01-01	66.2854321251268
2007-01-01	66.5792922673657
2008-01-01	66.8535530937585
2009-01-01	67.0621286611871
2010-01-01	67.1973726929897
2011-01-01	66.9962710795317
2012-01-01	66.7918998789651
2013-01-01	66.5598463744806
2014-01-01	66.2883343126539
2015-01-01	65.9729350811372
2016-01-01	65.7573223770882
2017-01-01	65.4775016789792