Year	Percent
1989	18.9503
1990	20.87118
1991	20.83936
1992	22.03818
1993	20.65334
1994	23.72078
1995	24.54088
1996	29.15229
1997	30.76462
1998	34.41864
1999	32.40021
2000	33.35913
2001	31.51139
2002	30.77736
2003	30.30814
2004	28.13184
2005	26.67177
2006	27.39161
2007	25.95792
2008	24.55437
2009	25.34038
2010	24.0166
2011	20.74202
2012	20.54185
2013	20.09333
2014	20.43144
2015	21.44172
2016	21.51317