Year	Percent
1971	97.13606
1972	99.16828
1973	98.96733
1974	100.15225
1975	107.80745
1976	105.94991
1977	105.39053
1978	102.44181
1979	101.94545
1980	103.4424
1981	100.41755
1982	100.95599
1983	100.0502
1984	100.04738
1985	102.15682
1986	101.68535
1987	100.33722
1988	99.76598
1989	100.10643
1990	100.59743
1991	97.88439
1992	98.37508
1994	99.66331
1995	98.31314
1996	98.95265
1997	95.55887
1999	99.91095
2000	100.64076
2001	103.52853
2002	101.89295
2003	102.21426
2004	100.71545
2005	99.0305
2006	99.30549
2007	101.32025
2008	104.60638
2009	102.38244
2010	102.89035
2011	104.04722
2012	100.55093
2013	100.02758
2014	100.32715
2015	100.42575