Year	Percent
1991	7.08
1993	8.51
1994	8.24
1995	7.15
1996	6.91
1997	6.65
1998	7.39
1999	7.32
2000	6.92
2001	5.68
2002	5.92
2003	6.48
2004	6.01
2005	6.51
2006	5.95
2007	4.82
2008	4.37
2009	5.86
2010	7.24
2011	8.17
2012	8.84
2013	10.1
2014	9.67
2015	8.96
2016	8
2017	6.56
2018	5.11
2019	4.45
2020	4.97