Year	Percent
1970	86.21701
1971	86.74352
1972	87.12871
1973	87.5
1974	87.99454
1975	88.47185
1976	88.93281
1977	89.37824
1978	89.80892
1979	90.11264
1980	90.64039
1981	91.0303
1982	91.41836
1983	91.79367
1984	92.26328
1985	92.61364
1986	92.95302
1987	93.38479
1988	93.81107
1989	94.11765
1990	94.52055
1991	94.90644
1992	95.28689
1993	95.55556
1994	95.91633
1995	96.16896
1996	96.60524
1997	96.9378
1998	97.16714
1999	97.48369
2000	97.79209
2001	98.09091
2002	98.3842
2003	98.67021
2004	98.86165
2005	99.22078
2006	99.4012
2007	99.66159
2008	99.91639
2009	100.16543
2010	100.40917
2011	100.56634
2012	100.72058
2013	100.95087
2014	101.09804
2015	101.31988