Year	Percent
1985	25.12563
1986	26.81282
1987	26.45161
1988	29.06977
1989	31.73913
1990	29.08093
1991	26.0355
1992	28.59351
1993	27.18864
1994	27.87197
1995	21.22239
1996	27.22093
1997	32.47997
1998	42.35028
1999	39.86497
2000	31.48155
2001	31.16843
2002	33.13206
2003	32.28803
2004	39.33065
2005	40.63234
2006	40.86768
2007	42.87052
2008	43.93179
2009	47.03687
2010	45.0919
2011	42.43177
2012	43.51867
2013	45.12788
2014	41.6356
2015	42.46802
2016	42.2547