Year	Percent
1990	6.13
1992	7.98
1993	8.05
1995	7.7
1996	6.89
1997	6.96
1998	6.72
1999	7.21
2000	3.97
2001	5.85
2002	5.82
2003	5.73
2004	5.74
2005	5.55
2006	4.94
2007	4.75
2008	3.95
2009	3.75
2011	2.69
2012	3.01
2013	2.97
2014	2.75
2015	2.74
2016	2.3
2017	2.39