Year	Percent
1970	92.43697
1971	92.7896
1972	93.24009
1973	93.57061
1974	94.00452
1975	94.31438
1976	94.61538
1977	95.11931
1978	95.40107
1979	95.67511
1980	96.04167
1981	96.40288
1982	96.75127
1983	97.09127
1984	97.42319
1985	97.65166
1986	97.96905
1987	98.27916
1988	98.58089
1989	98.87746
1990	99.07493
1991	99.35897
1992	99.63735
1993	99.91023
1994	100.17778
1995	100.35211
1996	100.60976
1997	100.94909
1998	101.11016
1999	101.35249
2000	101.58996
2001	101.73985
2002	101.96883
2003	102.19334
2004	102.33307
2005	102.46815
2006	102.68139
2007	102.8125
2008	102.94118
2009	103.14417
2010	103.26748
2011	103.38855
2012	103.50746
2013	103.62426
2014	103.66569
2015	103.85455