Year	Percent
1986	34.37547
1987	34.37
1988	33.40983
1989	33.192
1990	34.60944
1991	30.57777
1992	26.8755
1993	28.42585
1994	25.12564
1995	28.10933
1996	29.69902
1997	28.79002
1998	30.8544
1999	28.85706
2000	31.38226
2001	31.81576
2002	31.32163
2003	31.72386
2004	30.50823
2005	32.06007
2006	34.2754
2007	30.7664
2008	32.93284
2009	32.28873
2010	32.31383
2011	32.6144
2012	31.57676
2013	29.64071
2014	29.69406
2015	26.32464
2016	31.04822
2017	32.83339