Year	Percent
1976	7.62204
1977	13.56979
1978	15.68689
1979	14.61777
1980	16.30437
1981	16.79185
1982	18.18844
1983	21.64612
1984	25.28693
1985	27.53726
1986	31.98428
1987	32.87762
1988	24.60749
1989	24.75091
1990	27.00917
1991	26.5348
1992	21.94564
1993	23.08107
1994	20.86981
1995	18.27225
1996	17.83857
1997	17.13006
1998	16.80311
1999	17.50914
2000	22.06018
2001	14.42642
2002	15.47981
2003	14.60973
2004	15.44219
2005	13.67968
2006	15.59688
2007	12.25627
2008	7.87243
2009	10.47698
2010	10.4493
2011	11.5416
2012	11.4989
2013	10.90856
2014	8.41854
2015	11.25812
2016	10.7045