Year	Percent
1990	14.99
1991	16.48
1992	17.25
1993	17.21
1994	16.93
1995	16.23
1996	15.54
1997	14.81
1998	14.47
1999	15.41
2000	14.77
2001	14.15
2002	13.63
2003	13.28
2004	12.65
2005	12.29
2006	11.98
2007	11.63
2008	10.92
2009	10.25
2010	8.25
2011	5.8
2012	5.73
2013	7.58
2014	9.03
2015	8.03
2016	10.57
2017	10.95
2018	10.73
2019	11.9