Year	Percent
1990	10.34
1991	10.75
1992	9.2
1993	9.28
1994	9.25
1995	8.98
1996	9.13
1997	9.05
1998	8.95
1999	8.78
2000	8.54
2001	7.42
2002	8.55
2003	7.18
2004	7.34
2005	7.48
2006	6.59
2007	6.75
2008	5.95
2009	6.14
2010	6.15
2011	5.35
2012	5.33
2013	2.39
2014	2.44
2015	2.48
2016	2.51
2017	2.52
2018	2.51
2019	2.48