Year	Percent
1990	0.32
1991	0.642
1992	2.151
1993	3.381
1994	5.559
1995	4.088
1996	3.951
1997	4.2584
1998	3.3278
1999	3.909
2000	4.6768
2001	9.9796
2002	7.9247
2003	6.6096
2004	4.4525
2005	4.4886
2006	2.0814
2007	0.902
2008	3.0776
2009	7.3293
2010	13.9782
2011	9.0154
2012	5.3678
2013	4.367
2014	5.1491
2015	5.3603
2016	6.9168
2017	4.2859