Year	Percent
1976	2.4316
1977	1.82511
1978	1.52996
1979	0.68453
1980	2.68288
1981	3.5079
1982	4.18375
1983	2.20543
1984	1.37228
1985	1.28237
1986	0.71222
1987	0.94587
1988	0.60042
1989	0.77163
1990	0.62065
1991	0.95953
1992	3.3926
1993	3.84626
1994	2.76353
1995	1.46604
1996	1.2168
1997	1.63444
1998	2.9805
1999	1.52482
2000	3.49608
2001	2.04619
2002	3.41497
2003	1.9651
2004	1.89893
2005	2.20839
2006	9.42425
2007	3.89468
2008	5.79776
2009	3.50995
2010	3.02944
2011	0.94447
2012	3.45055
2013	2.28886
2014	2.15339
2015	2.24883
2016	1.4801
2017	2.01133