Year	Percent
1970	83.04498
1971	83.78378
1972	84.15842
1973	84.56592
1974	85.22013
1975	85.84615
1976	86.18619
1977	86.51026
1978	87.10602
1979	87.67507
1980	88.21918
1981	88.73995
1982	89.00524
1983	89.74359
1984	90.22556
1985	90.68627
1986	91.1271
1987	91.78404
1988	91.97248
1989	92.58427
1990	93.18681
1991	93.54839
1992	94.10526
1993	94.63918
1994	95.15152
1995	95.45455
1996	96.12403
1997	96.58444
1998	97.02602
1999	97.44991
2000	97.86096
2001	98.25175
2002	98.63014
2003	99.32773
2004	99.67051
2005	100
2006	100.31646
2007	100.7764
2008	101.21951
2009	101.49477
2010	101.90616
2011	102.30548
2012	102.68741
2013	103.05556
2014	103.27422
2015	103.61446