Year	Percent of Total
1960-01-01	66.3539113048038
1961-01-01	66.1906267294813
1962-01-01	66.1165262200862
1963-01-01	66.1270753436125
1964-01-01	66.1809246556278
1965-01-01	66.2418358395407
1966-01-01	66.2152956312975
1967-01-01	66.2147667794837
1968-01-01	66.2217141622712
1969-01-01	66.2187467051970
1970-01-01	66.1980352918170
1971-01-01	66.1408309582861
1972-01-01	66.0757625167019
1973-01-01	66.0165280509928
1974-01-01	65.9909093938391
1975-01-01	66.0072627953323
1976-01-01	65.8693477014021
1977-01-01	65.7990330281621
1978-01-01	65.7818717668553
1979-01-01	65.8039109105609
1980-01-01	65.8624721588458
1981-01-01	65.9810509389955
1982-01-01	66.1153619658042
1983-01-01	66.2500166509038
1984-01-01	66.3725955350685
1985-01-01	66.4668282977436
1986-01-01	66.4186902234522
1987-01-01	66.3440363897040
1988-01-01	66.2511379677175
1989-01-01	66.1721777026455
1990-01-01	66.1550098962333
1991-01-01	65.9069315308274
1992-01-01	65.7650857109041
1993-01-01	65.7213188455565
1994-01-01	65.7380826069441
1995-01-01	65.7823595417802
1996-01-01	66.1365021414424
1997-01-01	66.4643740325778
1998-01-01	66.7691541934796
1999-01-01	67.0780295329284
2000-01-01	67.3993218555770
2001-01-01	67.5472739304850
2002-01-01	67.6860013364846
2003-01-01	67.8293317328388
2004-01-01	67.9688903719295
2005-01-01	68.0881762817486
2006-01-01	67.9983724858204
2007-01-01	67.9173437137296
2008-01-01	67.8000197057278
2009-01-01	67.6117470037355
2010-01-01	67.3427410213332
2011-01-01	66.9239090096797
2012-01-01	66.4937272347151
2013-01-01	66.0397560458852
2014-01-01	65.5555125728273
2015-01-01	65.0476955815349
2016-01-01	64.6535237366680
2017-01-01	64.1803193568880