Year	Percent
1974	0.17978
1975	0.25541
1976	0.0195
1977	0.04601
1978	0.05219
1979	0.0839
1980	0.02617
1981	0.13373
1982	0.08521
1983	0.07458
1984	0.18837
1985	0.14724
1986	0.16506
1987	0.13192
1988	0.38964
1989	0.6188
1990	0.45395
1991	0.5399
1992	0.53263
1993	0.353
1994	0.46522
1995	0.52217
1996	0.39785
1997	0.42405
1998	0.34087
1999	0.306
2000	0.35973
2001	1.67389
2002	0.45381
2003	0.54582
2004	0.68802
2005	2.00053
2006	3.65348
2007	3.2625
2008	2.59716
2009	1.33175
2010	1.17878
2011	1.94373
2012	1.57257
2013	1.42681
2014	1.40432
2015	2.09375
2016	1.54483
2017	1.2794