Year	Percent
1970	77.57499
1971	78.68374
1972	88.48335
1973	91.42205
1974	89.61235
1975	89.41889
1976	83.97226
1977	91.47518
1978	88.20134
1979	84.32705
1980	84.66959
1981	88.41767
1982	89.18018
1985	79.28998
1986	78.97844
1987	76.14669
1988	76.97266
1989	76.66038
1991	81.11777
1992	83.12035
1993	84.61127
1994	83.78415
1995	82.95369
1996	86.22211
1999	88.42013
2000	93.39455
2001	96.08189
2002	96.81372
2004	96.84384
2005	95.69374
2006	92.74159
2007	94.69051
2008	96.79768
2009	98.48847
2010	99.93457
2011	105.87951
2012	103.69792
2013	99.31541
2014	98.45296
2015	99.77004
2016	97.26297