Year	Percent
1990	6.92
1991	7.33
1992	7.43
1993	7.92
1994	8.3
1995	8.16
1996	7.96
1997	7.69
1998	7.43
1999	7.17
2000	6.91
2001	6.64
2002	6.37
2003	6.11
2004	5.86
2005	5.62
2006	5.41
2007	5.2
2008	5.01
2009	4.82
2010	5.51
2011	4.69
2012	3.98
2013	4.7
2014	3.64
2015	4.16
2016	4.77
2017	5.47
2018	5.53
2019	5.62