Year	Percent
1970	91.5873
1971	92.05607
1972	92.36641
1973	92.8036
1974	93.37261
1975	93.77713
1976	94.17614
1977	94.69274
1978	95.06173
1979	95.54656
1980	95.88859
1981	96.21904
1982	96.79076
1983	97.09596
1984	97.63682
1985	97.91922
1986	98.43185
1987	98.81094
1988	99.06323
1989	99.53811
1990	99.8861
1991	100.33708
1992	100.77691
1993	101.09529
1994	101.51515
1995	101.81624
1996	102.21753
1997	102.50522
1998	102.88958
1999	103.16004
2000	103.52823
2001	103.78486
2002	104.13386
2003	104.37743
2004	104.61538
2005	104.94297
2006	105.16917
2007	105.29248
2008	105.60147
2009	105.71688
2010	105.91928
2011	106.02837
2012	106.22261
2013	106.41804
2014	106.51801
2015	106.61578