Year	Percent
1971	64.91327
1972	58.36622
1973	65.51316
1974	75.48843
1975	79.6341
1976	93.69411
1977	111.33939
1978	119.56763
1979	114.39204
1980	105.84486
1981	96.94079
1982	87.15941
1983	95.86826
1984	100.51178
1985	97.43561
1986	94.29142
1987	97.18809
1988	95.31641
1989	96.2121
1990	93.87616
1991	94.151
1992	86.63637
1993	83.79512
1994	96.54062
1995	96.93307
1996	97.50993
1999	94.59031
2000	96.27994
2001	95.94343
2002	100.85803
2003	96.19925
2004	93.07577
2005	93.4402
2006	91.70024
2007	91.92276
2008	88.06213
2009	96.05567
2010	96.42297
2011	97.81887
2012	96.87398
2013	95.8527
2014	100.30573
2015	99.33975