Year	Percent of Total
1960-01-01	65.6826600734705
1961-01-01	65.8411601064271
1962-01-01	65.9156561898265
1963-01-01	65.9678823308846
1964-01-01	66.0859052078559
1965-01-01	66.2942845924913
1966-01-01	66.5640058712571
1967-01-01	66.8220953354812
1968-01-01	67.0815280512244
1969-01-01	67.3442660405022
1970-01-01	67.5956702172609
1971-01-01	67.5279719788791
1972-01-01	67.5757253732008
1973-01-01	67.6225409075517
1974-01-01	67.5067233203714
1975-01-01	67.1594344972628
1976-01-01	66.6913993222263
1977-01-01	65.9583139083468
1978-01-01	65.1483673434464
1979-01-01	64.5691421628692
1980-01-01	64.3857895188050
1981-01-01	64.2936241615422
1982-01-01	64.6866033539113
1983-01-01	65.3470160762826
1984-01-01	65.9187253325537
1985-01-01	66.2100422482948
1986-01-01	66.4713521738940
1987-01-01	66.3529845512791
1988-01-01	66.0725917190406
1989-01-01	65.9513353327964
1990-01-01	66.1301290629257
1991-01-01	66.1254371565612
1992-01-01	66.4361521025436
1993-01-01	66.9209270753888
1994-01-01	67.3597588443156
1995-01-01	67.6534550589101
1996-01-01	67.7884879196136
1997-01-01	67.8568054273237
1998-01-01	67.8863381790821
1999-01-01	67.9482717930872
2000-01-01	68.0743399088802
2001-01-01	68.2486814554240
2002-01-01	68.4057490102157
2003-01-01	68.5583136034114
2004-01-01	68.7134388740930
2005-01-01	68.8645427312741
2006-01-01	68.8186543676810
2007-01-01	68.8281402214530
2008-01-01	68.8902465279199
2009-01-01	68.9732905362839
2010-01-01	69.0479802253058
2011-01-01	68.9249079934097
2012-01-01	68.7971772956459
2013-01-01	68.6302270838048
2014-01-01	68.3898898794345
2015-01-01	68.0632466009296
2016-01-01	67.6336506658631
2017-01-01	67.1058109095465