Year	Percent
1970	93.59504
1971	94.32049
1972	94.83101
1973	95.32164
1974	95.80153
1975	96.44195
1976	97.05882
1977	97.47748
1978	98.23009
1979	98.78472
1980	99.31857
1981	99.83278
1982	100.32841
1983	100.80645
1984	101.26582
1985	101.86625
1986	102.29008
1987	102.69865
1988	103.39233
1989	103.61795
1990	104.12518
1991	104.61538
1992	104.94505
1993	105.40541
1994	105.84329
1995	106.13577
1996	106.41026
1997	106.67506
1998	106.93069
1999	107.17762
2000	107.41627
2001	107.52056
2002	107.74566
2003	107.96359
2004	108.28667
2005	108.37004
2006	108.56833
2007	108.64461
2008	108.83281
2009	109.00621
2010	109.18367
2011	109.24623
2012	109.41526
2013	109.47266
2014	109.63391
2015	109.69582