Year	Percent
1970	91.67862
1971	92.11268
1972	92.53112
1973	92.93478
1974	93.45794
1975	93.83202
1976	94.19355
1977	94.67005
1978	94.88778
1979	95.33742
1980	95.77295
1981	96.0761
1982	96.48712
1983	96.77047
1984	97.26962
1985	97.53363
1986	97.79006
1987	98.14613
1988	98.493
1989	98.83103
1990	99.16055
1991	99.37824
1992	99.69294
1993	100
1994	100.3003
1995	100.49456
1996	100.88149
1997	101.06486
1998	101.341
1999	101.61137
2000	101.78069
2001	102.04082
2002	102.29358
2003	102.45009
2004	102.693
2005	102.93073
2006	103.16344
2007	103.3913
2008	103.52537
2009	103.74468
2010	103.87205
2011	103.99667
2012	104.20445
2013	104.40457
2014	104.51977
2015	104.63259