Year	Percent
1970	92.01389
1971	92.54237
1972	93.06931
1973	93.56913
1974	94.04389
1975	94.20732
1976	94.94048
1977	95.36232
1978	95.76271
1979	95.87912
1980	96.51475
1981	96.86684
1982	97.20102
1983	97.76675
1984	98.06763
1985	98.35294
1986	98.85321
1987	99.10515
1988	99.56427
1989	99.78769
1990	100.20704
1991	100.60606
1992	100.7874
1993	101.15385
1994	101.31332
1995	101.83486
1996	102.1544
1997	102.46479
1998	102.9361
1999	103.21489
2000	103.64842
2001	104.07166
2002	104.47284
2003	104.85893
2004	105.23077
2005	105.42986
2006	105.77778
2007	106.2591
2008	106.42857
2009	106.73212
2010	107.02479
2011	107.30717
2012	107.57979
2013	107.97386
2014	108.22622
2015	108.47029