Year	Percent
1970	93.88298
1971	94.25587
1972	94.73684
1973	95.08197
1974	95.41512
1975	95.85871
1976	96.28297
1977	96.58019
1978	96.98376
1979	97.26027
1980	97.64045
1981	97.89823
1982	98.25708
1983	98.49785
1984	98.83721
1985	99.1658
1986	99.48613
1987	99.69605
1988	100
1989	100.19724
1990	100.48685
1991	100.67308
1992	100.85389
1993	101.03093
1994	101.2037
1995	101.4652
1996	101.62896
1997	101.78891
1998	101.9469
1999	102.18914
2000	102.25108
2001	102.485
2002	102.54237
2003	102.76846
2004	102.90698
2005	103.125
2006	103.17331
2007	103.30379
2008	103.43176
2009	103.55731
2010	103.6805
2011	103.8014
2012	103.92006
2013	104.03656
2014	104.15094
2015	104.26647