Year	Percent
1978	0.03723
1979	1.89489
1980	0.35076
1981	0.59863
1982	0.60122
1983	0.82438
1984	2.32911
1985	4.48757
1986	5.56803
1987	10.05531
1988	6.69048
1989	9.21483
1990	11.84223
1991	11.51535
1992	5.48577
1993	5.79123
1994	8.19767
1995	3.83655
1996	3.8682
1997	2.49292
1998	5.99796
1999	4.8483
2000	7.10726
2001	7.1635
2002	10.96382
2003	9.8676
2004	14.64209
2005	9.0784
2006	2.46424
2007	5.97889
2008	5.41156
2009	4.21143
2010	6.18319
2011	2.70247
2012	4.57658
2013	7.30928
2014	2.82453
2015	2.44126
2016	3.86732