Year	Percent
1975	6.48584
1976	5.8088
1977	3.71509
1978	7.41414
1979	8.89464
1980	13.11087
1981	14.25083
1982	15.55681
1983	30.41122
1984	21.72094
1985	23.57944
1986	28.32366
1987	45.80234
1988	56.91739
1989	50.77058
1990	38.791
1991	28.13394
1992	28.35191
1993	25.63847
1994	26.68999
1995	25.43817
1996	27.56922
1997	33.247
1998	22.76087
1999	21.14556
2000	19.03769
2001	12.93067
2002	8.5925
2003	15.6254
2004	8.03323
2005	8.61579
2006	5.57617
2007	3.85781
2008	4.11961
2009	3.75531
2010	3.99223
2011	2.40487
2012	3.17818
2013	6.0584
2014	5.43512
2015	6.25005
2016	10.49294