Year	Percent
1976	88.46418
1977	91.43935
1978	80.81866
1979	78.53592
1980	91.50556
1981	78.01652
1982	76.45857
1983	73.70823
1984	80.67537
1985	88.74354
1986	91.07951
1987	99.37765
1988	105.20253
1989	105.47229
1990	105.97404
1991	96.36351
1992	90.78031
1993	92.35856
1994	92.09876
1995	86.97275
1996	92.51587
1997	90.29539
1998	89.16785
1999	88.57718
2000	79.64989
2001	79.67353
2002	83.07821
2003	75.96449
2004	74.60519
2005	84.34849
2006	84.73104
2007	75.23223
2008	70.42185
2009	62.12462
2010	66.44713
2011	66.96946
2012	68.58858
2013	68.14603
2014	67.9828
2015	63.73521
2016	57.47723
2017	57.09492