Year	Percent
1970	96.91211
1971	97.31308
1972	97.6985
1973	98.07475
1974	98.43924
1975	98.79254
1976	99.13514
1977	99.46752
1978	99.6852
1979	99.89669
1980	100.20367
1981	100.50201
1982	100.89197
1983	101.17302
1984	101.44648
1985	101.71265
1986	101.87793
1987	102.22635
1988	102.38095
1989	102.71493
1990	102.8597
1991	103.09187
1992	103.31878
1993	103.54059
1994	103.67208
1995	103.80068
1996	104.01338
1997	104.22185
1998	104.3407
1999	104.54177
2000	104.57464
2001	104.76948
2002	104.88189
2003	104.9922
2004	105.10046
2005	105.20674
2006	105.31108
2007	105.41353
2008	105.43964
2009	105.46529
2010	105.64103
2011	105.66449
2012	105.69164
2013	105.71429
2014	105.74061
2015	105.83685