Year	Percent
1970	98.03408
1971	98.45361
1972	98.85932
1973	99.12827
1974	99.5098
1975	99.87937
1976	100.11862
1977	100.35006
1978	100.8046
1979	101.0181
1980	101.3363
1981	101.53509
1982	101.83585
1983	102.02128
1984	102.30608
1985	102.58264
1986	102.74949
1987	103.01205
1988	103.16832
1989	103.31707
1990	103.46487
1991	103.60531
1992	103.74532
1993	103.87812
1994	103.91621
1995	104.04313
1996	104.16298
1997	104.27948
1998	104.30293
1999	104.32937
2000	104.43886
2001	104.46281
2002	104.48613
2003	104.50886
2004	104.61416
2005	104.63472
2006	104.73602
2007	104.75825
2008	104.77997
2009	104.87988
2010	104.89978
2011	104.92285
2012	104.94545
2013	105.04323
2014	105.06781
2015	105.09194