Year	Percent
1990	9.41
1992	11.91
1993	11.84
1995	11.9
1996	10.23
1997	10.73
1998	10.14
1999	10.98
2000	5.5
2001	8.55
2002	8.51
2003	8.27
2004	8.09
2005	8.12
2006	7.17
2007	6.8
2008	5.88
2009	5.54
2011	4.14
2012	4.58
2013	4.59
2014	4.26
2015	4.18
2016	3.52
2017	3.61