Year	Percent
1970	96.7587
1971	97.15976
1972	97.54959
1973	98.04147
1974	98.40909
1975	98.76543
1976	99.11406
1977	99.45295
1978	99.78378
1979	100.2139
1980	100.52854
1981	100.94142
1982	101.24224
1983	101.53689
1984	101.82741
1985	102.11268
1986	102.39282
1987	102.66798
1988	102.94118
1989	103.21324
1990	103.38164
1991	103.64683
1992	103.91221
1993	104.07583
1994	104.43396
1995	104.59662
1996	104.65116
1997	104.89381
1998	105.03663
1999	105.08167
2000	105.22052
2001	105.35236
2002	105.38869
2003	105.6042
2004	105.72917
2005	105.84695
2006	105.87734
2007	105.99156
2008	106.10368
2009	106.12583
2010	106.31665
2011	106.33631
2012	106.44122
2013	106.53907
2014	106.55608
2015	106.57277