Year	Percent
1990	26.11193
1991	26.33528
1992	27.23177
1993	25.12535
1994	24.64953
1995	19.7898
1996	16.63759
1997	14.89974
1998	20.10575
1999	17.53939
2000	16.81557
2001	17.4472
2002	17.19001
2003	19.16681
2004	22.56985
2005	21.4718
2006	26.03955
2007	32.84936
2008	32.07616
2009	25.12516
2010	27.29603
2011	33.24037
2012	28.50287
2013	30.32429
2014	30.13071
2015	27.20535
2016	24.77317