Year	Percent
1970	89.6732
1971	90.10283
1972	90.64475
1973	91.0559
1974	91.45299
1975	91.82692
1976	92.31678
1977	92.67442
1978	93.02059
1979	93.46847
1980	93.79157
1981	94.21397
1982	94.51613
1983	94.91525
1984	95.30271
1985	95.67901
1986	96.04462
1987	96.4
1988	96.74556
1989	97.08171
1990	97.31286
1991	97.63258
1992	97.94393
1993	98.24723
1994	98.54281
1995	98.74101
1996	99.11111
1997	99.29763
1998	99.56635
1999	99.82847
2000	100.08482
2001	100.33529
2002	100.58043
2003	100.73831
2004	100.97403
2005	101.20482
2006	101.35135
2007	101.57356
2008	101.7134
2009	101.85042
2010	102.06264
2011	102.19365
2012	102.32384
2013	102.526
2014	102.65096
2015	102.77372