Year	Percent
1989	32.16239
1990	32.52997
1991	32.4015
1992	32.56329
1993	31.46513
1994	30.99909
1995	30.30064
1996	30.75879
1997	31.72875
1998	33.21589
1999	34.25823
2000	33.71751
2001	32.61653
2002	31.7455
2003	30.69758
2004	32.82329
2005	32.74444
2006	30.057
2007	27.22266
2008	25.92033
2009	21.48769
2010	19.96801
2011	18.10568
2012	17.77689
2013	17.8187
2014	18.22938
2015	18.99152
2016	19.95872