Year	% of total
1960	91.14805621570406
1961	91.19144207501691
1962	91.78950899432684
1963	91.99572478646634
1964	92.67797122262348
1965	92.68585722392939
1966	93.11888916183618
1967	94.4052172459684
1968	94.72148855185715
1969	95.23342118969605
1970	95.52565262261086
1971	72.97008621907129
1972	73.74900645497671
1973	75.0956033468099
1974	74.62725187604396
1975	74.83156040742372
1976	75.39160905496524
1977	76.70228660431268
1978	76.9825509056768
1979	76.98601348074396
1980	76.20906123168866
1981	75.43414202837825
1982	75.06548108740805
1983	75.06475883372437
1984	75.47822564321682
1985	74.91536252008729
1986	75.29719595522106
1987	75.33150733433109
1988	76.40001355620392
1989	76.55935919156941
1990	77.0420466511168
1991	76.68828066323618
1992	77.26621616408978
1993	77.77506350451881
1994	78.3424010092597
1995	78.80392075799325
1996	79.17434459591334
1997	79.21677269306417
1998	78.65015110662097
1999	79.13821678308949
2000	79.19559548414736
2001	79.84971034638978
2002	80.57916429371834
2003	82.0243363920613
2004	82.81005273398134
2005	83.25583853364672
2006	83.90158360304147
2007	84.74013955891188
2008	84.5400858662495
2009	84.54991928702403
2010	85.16201539665532
2011	86.59731780993042
2012	86.74263228281538
2013	86.7237300526565
2014	86.3961530004804
2015	87.88536414825094