Year	Percent
1983	8.04
1984	8.01
1985	7.11
1986	5.71
1987	5.37
1988	6.1
1989	7.47
1990	7.95
1991	8.67
1992	8.46
1993	10.25
1994	7.79
1995	6.16
1996	6.04
1997	4.85
1998	4.58
1999	4.28
2000	4.07
2001	3.47
2002	3.74
2003	4.96
2004	4.7
2005	4.09
2006	3.17
2007	3.12
2008	2.72
2009	5.4
2010	6.68
2011	6.55
2012	6.77
2013	6.5
2014	6.03
2015	5.69
2016	5.31
2017	5.11
2018	4.51
2019	4.51
2020	4.92