Year	Percent
1970	82.01754
1971	82.40343
1972	82.98319
1973	83.53909
1974	84.07258
1975	84.41815
1976	85.10638
1977	85.60606
1978	86.08534
1979	86.54545
1980	87.32143
1981	87.91594
1982	88.16467
1983	88.72054
1984	89.42149
1985	89.93506
1986	90.44586
1987	90.92332
1988	91.53846
1989	91.99396
1990	92.57058
1991	93.27485
1992	93.67816
1993	94.20085
1994	94.71488
1995	95.20548
1996	95.81646
1997	96.14874
1998	96.60131
1999	97.16495
2000	97.58883
2001	98
2002	98.27798
2003	98.78788
2004	99.16368
2005	99.52941
2006	99.88413
2007	100.22831
2008	100.56243
2009	100.88692
2010	101.20219
2011	101.507
2012	101.80467
2013	102.09205
2014	102.37358
2015	102.64496