Year	Percent
1989	17.64
1990	21.26
1991	20.6
1992	24.38
1993	26.23
1994	27.74
1995	31.84
1997	25.43
2000	29.77
2001	27.3
2002	25.9
2003	23.72
2004	17.65
2005	15.27
2006	12.27
2007	13.79
2008	11.33
2009	10.16
2010	9.96
2011	9.96
2012	10.97
2013	9.82
2014	10.21
2015	11.21
2016	10.2
2017	13.57