Year	Percent
1990	24.23871
1991	22.19091
1992	25.29612
1993	26.36788
1994	29.67272
1995	33.7323
1996	35.59556
1997	32.31607
1998	30.33155
1999	29.16233
2000	31.40788
2001	31.54924
2002	30.12562
2003	29.03908
2004	29.34894
2005	29.12469
2006	30.04403
2007	32.07228
2008	31.06182
2009	26.51317
2010	27.12269
2011	26.95754
2012	26.18564
2013	24.66704
2014	25.88038
2015	27.95578
2016	26.33976
2017	26.33769