Year	Percent
1970	89.9529
1971	90.44684
1972	90.92284
1973	91.24629
1974	91.83673
1975	92.13162
1976	92.55618
1977	92.96552
1978	93.49593
1979	93.87483
1980	94.24084
1981	94.72329
1982	95.06953
1983	95.52239
1984	95.84352
1985	96.26955
1986	96.56805
1987	96.97322
1988	97.25086
1989	97.74266
1990	98
1991	98.35886
1992	98.7069
1993	99.04459
1994	99.37238
1995	99.58805
1996	99.89848
1997	100.2002
1998	100.39448
1999	100.77821
2000	100.95877
2001	101.2299
2002	101.49393
2003	101.65746
2004	101.90909
2005	102.1544
2006	102.39362
2007	102.44969
2008	102.67934
2009	102.8181
2010	103.125
2011	103.25543
2012	103.38284
2013	103.59184
2014	103.63196
2015	103.83387