Year	Percent
1979	5.69
1980	4.11
1982	5.61
1983	8.25
1984	7.33
1985	5.13
1986	6.1
1987	5.51
1988	4.72
1989	5.62
1990	5.8
1991	5.1
1992	4.98
1993	5.06
1994	4.41
1995	3.4
1996	8.15
1997	5.36
1998	4.42
1999	5.34
2000	7.61
2001	6.21
2002	9.39
2003	6.81
2004	6.51
2005	4.82
2006	5.28
2007	4.71
2008	4.42
2009	5.46
2010	4.57
2011	4.67
2012	4.09
2013	4.38
2014	5.03
2015	4.56
2016	5.25
2017	4.61
2018	6.22
2019	6.59
2020	7.55