Year	Percent
1970	89.40299
1971	89.7511
1972	90.21583
1973	90.80622
1974	91.11111
1975	91.53005
1976	91.94631
1977	92.33818
1978	92.72727
1979	93.09463
1980	93.57683
1981	93.92813
1982	94.26129
1983	94.70517
1984	95.01779
1985	95.32164
1986	95.84296
1987	96.12756
1988	96.51294
1989	96.77778
1990	97.14599
1991	97.39696
1992	97.74678
1993	98.08917
1994	98.42437
1995	98.7513
1996	99.07216
1997	99.28498
1998	99.59514
1999	99.8998
2000	100.19861
2001	100.49164
2002	100.77897
2003	101.06075
2004	101.33588
2005	101.60681
2006	101.87091
2007	102.12963
2008	102.38313
2009	102.53853
2010	102.78276
2011	103.01954
2012	103.16344
2013	103.3913
2014	103.5284
2015	103.74787