Year	Percent
1990	14.83
1991	14.84
1992	11.91
1993	11.23
1994	11.06
1995	9.44
1996	9.87
1997	9.3
1998	9.25
1999	9.62
2000	9.49
2001	9.26
2002	8.86
2003	9.39
2004	8.18
2005	7.49
2006	8.27
2007	8.86
2008	9.53
2009	10.03
2010	9.27
2011	9.67
2012	10.04
2013	10.53
2014	11.32
2015	11.57
2016	12.14
2017	11.99
2018	12.03
2019	11.34