Year	Percent
1976	79.76379
1977	82.90846
1978	79.82147
1979	86.73791
1980	85.31078
1981	98.53662
1982	94.29056
1983	81.33886
1984	79.54653
1985	76.25732
1986	53.53756
1987	57.71021
1988	64.68033
1989	74.40148
1990	89.61626
1991	79.87153
1992	81.40659
1993	80.15242
1994	70.45762
1995	72.8631
1996	78.17057
1997	71.48607
1998	64.25684
1999	61.16577
2000	68.50447
2001	67.15051
2002	66.618
2003	68.33433
2004	82.4344
2005	94.20681
2006	87.87336
2007	91.75853
2008	87.51065
2009	69.09502
2010	69.02988
2011	73.85899
2012	74.26475
2013	71.954
2014	69.73825
2015	60.4891
2016	56.1741
2017	57.02761