Year	Percent
1990	11.8
1991	12.11
1992	12.45
1993	10.66
1994	11.43
1995	9.63
1996	12.15
1997	11.19
1998	10.29
1999	9.45
2000	8.67
2001	8.8
2002	8.94
2003	9.08
2004	9.23
2005	9.37
2006	9.53
2007	9.7
2008	9.87
2009	10.06
2010	11.22
2011	13
2012	12.17
2013	13.75
2014	14.01
2015	14.47
2016	14.27
2017	13.65
2018	13.93
2019	14.17