Year	% of total
1960	85.90669210510141
1961	86.25191180816242
1962	87.06993431775336
1963	87.12821768904526
1964	87.97580658701722
1965	88.04199102012956
1966	89.24176866837296
1967	89.50084988008544
1968	90.10461479015234
1969	90.26962042823561
1970	91.53110974448676
1971	91.17777518588038
1972	91.30558851050577
1973	92.09782489114325
1974	91.82731595665142
1975	91.78090792960361
1976	91.88762257738466
1977	92.67901978303821
1978	92.65498939990758
1979	92.82094106708088
1980	93.18251205126165
1981	92.77557890068321
1982	92.9254455862167
1983	92.84942864135523
1984	93.20671425519726
1985	92.87885472992308
1986	93.4217424604167
1987	93.73860918426544
1988	93.57842828188258
1989	93.85217111440396
1990	93.91128568601698
1991	93.68871803625748
1992	94.34266007380121
1993	93.75834560953615
1994	93.88648311648664
1995	93.83177016576778
1996	93.64822076296562
1997	93.51265088985517
1998	93.87865070879005
1999	93.92791207166783
2000	89.32816819002298
2001	98.0530884338196
2002	95.89021478723635
2003	93.88602451318003
2004	94.06821267120928
2005	94.21585218232413
2006	94.28316544661021
2007	94.29310395131101
2008	94.35148822698058
2009	95.51005853499287
2010	94.42474221531253
2011	94.42165586113602
2012	94.37700611510014
2013	93.70804882449004
2014	93.386835655426
2015	89.62563011023737