Year	Percent
1975	3.66966
1976	4.55512
1977	4.73288
1978	6.41298
1993	2.01871
1994	3.90165
1995	9.50194
1996	14.13944
1997	13.32634
1998	13.5144
1999	19.172
2000	24.35007
2001	5.81755
2002	9.14316
2003	17.93885
2004	22.41615
2005	16.0918
2006	13.63677
2007	12.54282
2008	11.99611
2009	14.2935
2010	17.78833
2011	18.35297
2012	15.195
2013	73.97639
2014	26.84586
2015	23.17542
2016	26.58915
2017	24.71704