Year	Percent
1990	14.03
1991	13.79
1992	13.29
1993	13.33
1994	13.6
1995	13.25
1996	13.82
1997	12.47
1998	11.01
1999	10.35
2000	11.96
2001	9.84
2002	9.68
2003	10.8
2004	10.12
2005	10.37
2006	10.28
2007	11.09
2008	10.5
2009	9.87
2010	9.15
2011	10.34
2012	10.71
2013	9.34
2014	11.14
2015	9.31
2016	7.17
2017	6.44
2018	7.04
2019	8.78