Year	Percent
1988	0.04826
1989	0.56298
1990	0.47359
1991	1.85296
1992	2.40027
1993	3.50595
1994	3.25843
1995	4.57513
1996	7.78612
1997	5.03681
1998	4.7634
1999	5.2808
2000	5.67335
2001	5.8366
2002	6.8287
2003	10.2728
2004	9.30858
2005	9.42612
2006	12.13805
2007	14.18794
2008	15.51294
2009	14.39676
2010	16.9801
2011	15.66429
2012	15.61472
2013	10.87141
2014	10.69106
2015	8.10314
2016	6.21134