Year	Percent
1976	22.56885
1977	24.83973
1978	53.45878
1979	34.109
1980	35.46036
1981	36.21016
1982	59.74891
1983	51.8604
1984	63.8809
1985	50.29821
1986	37.44768
1987	34.33508
1988	54.93004
1989	33.50219
1990	39.36796
1991	35.72226
1992	37.25041
1993	37.89394
1994	29.54534
1995	29.98273
1996	31.24477
1997	31.85174
1998	29.61682
1999	28.91273
2000	39.84335
2001	33.52441
2002	29.10943
2003	21.39675
2004	19.75652
2005	15.65082
2006	9.68704
2007	13.94557
2008	12.89617
2009	10.32769
2010	9.47087
2011	4.81414
2012	5.23591
2013	4.26871
2014	6.95013
2015	9.72914
2016	9.28692