Year	Percent
1965	36.89803
1966	37.49499
1967	37.79825
1968	30.94396
1969	33.48201
1970	33.90683
1971	33.36538
1972	34.90794
1973	40.4212
1974	57.79716
1975	52.65787
1976	51.4052
1977	53.89611
1978	54.70184
1979	64.54641
1980	65.62113
1981	74.6395
1982	66.46666
1983	59.36401
1984	60.1825
1985	53.4471
1986	51.55167
1987	53.40197
1988	60.25974
1989	72.30198
1990	73.5442
1991	67.97819
1992	67.43116
1993	68.56073
1994	71.88246
1995	74.1894
1996	67.47221
1997	64.94151
1998	64.61386
1999	62.52701
2000	67.13954
2001	73.2345
2002	70.86704
2003	68.9784
2004	72.16243
2005	73.34488
2006	77.66975
2007	88.06597
2008	97.9975
2009	77.18642
2010	87.72101
2011	91.24322
2012	92.08318
2013	89.46281
2014	87.38197
2015	79.46376
2016	78.53504
2017	86.58844