Year	Percent
1994	27.969
1995	26.012
1996	20.584
1997	22.679
1998	25.3104
1999	33.0876
2000	40.0113
2001	42.5753
2002	38.8133
2003	34.7586
2004	34.8148
2005	31.0095
2006	26.4134
2007	20.4358
2008	18.4988
2009	27.7864
2010	34.6341
2011	33.1938
2012	34.9683
2013	34.9329
2014	29.4529
2015	25.7906
2016	19.7675
2017	18.1327