Year	Percent
1983	6.19
1984	5.06
1985	5.93
1986	5
1987	5.87
1988	5.92
1989	7.14
1990	6.12
1991	8.61
1992	8.56
1993	8.82
1994	6.47
1995	8.02
1996	6.11
1997	5.06
1998	5.08
1999	4.24
2000	4.04
2001	3.97
2002	4.68
2003	3.9
2004	5.63
2005	5.17
2006	3.89
2007	3.42
2008	2.55
2009	4.53
2010	5.73
2011	5.75
2012	5.8
2013	5.52
2014	5.2
2015	4.38
2016	4.1
2017	3.7
2018	3.64
2019	3.37
2020	4.2