Year	Percent
1993	32.77
1994	33.49
1995	29.84
1997	29.97
1998	23.27
1999	21.99
2000	26.01
2001	17.02
2002	19.52
2003	25.75
2004	32.15
2005	31.49
2006	32.62
2007	33.94
2008	34.68
2009	33.22
2010	29.28
2011	30.06
2012	27.51
2013	34.65
2014	36.69
2015	39.89
2016	23.43
2017	26.33