Year	Percent
1970	94.16168
1971	94.56681
1972	94.81268
1973	95.19095
1974	95.55556
1975	95.90723
1976	96.24665
1977	96.57444
1978	96.76585
1979	97.20102
1980	97.375
1981	97.78598
1982	97.94438
1983	98.21641
1984	98.36257
1985	98.73272
1986	98.97959
1987	99.21875
1988	99.34066
1989	99.5671
1990	99.78678
1991	100
1992	100.10352
1993	100.30612
1994	100.40241
1995	100.59524
1996	100.88149
1997	101.0628
1998	101.23928
1999	101.4111
2000	101.7658
2001	101.92661
2002	102.08333
2003	102.32766
2004	102.47569
2005	102.70979
2006	102.84974
2007	103.0743
2008	103.20946
2009	103.3389
2010	103.55078
2011	103.67647
2012	103.79951
2013	104
2014	104.11718
2015	104.15361