Year	Percent
1970	86.91358
1971	87.51515
1972	88.09524
1973	88.75878
1974	89.29804
1975	89.819
1976	90.43382
1977	91.02845
1978	91.60388
1979	92.26695
1980	92.70833
1981	93.33333
1982	93.93939
1983	94.52736
1984	95.09804
1985	95.55985
1986	96.1941
1987	96.7167
1988	97.22479
1989	97.71898
1990	98.19982
1991	98.75556
1992	99.12281
1993	99.56672
1994	99.91438
1995	100.3387
1996	100.58676
1997	100.82988
1998	101.06908
1999	101.30293
2000	101.53226
2001	101.67732
2002	101.90024
2003	102.11765
2004	102.2533
2005	102.38645
2006	102.59542
2007	102.72315
2008	102.92573
2009	102.97398
2010	103.17109
2011	103.21637
2012	103.33575
2013	103.52518
2014	103.56633
2015	103.60934