Year	Percent
1990	1.599
1991	3.02
1992	6.898
1993	9.36
1994	10.998
1995	12.357
1996	15.194
1997	21.0235
1998	17.158
1999	22.223
2000	22.1381
2001	18.2021
2002	17.2068
2003	23.7922
2004	26.833
2005	16.1127
2006	9.9775
2007	12.1768
2008	12.6101
2009	31.5584
2010	35.6589
2011	23.8181
2012	22.8284
2013	17.758
2014	19.2777
2015	13.8218
2016	15.8244
2017	13.8826