Year	Percent
1982	5.45
1983	4.29
1984	4.47
1985	4.85
1986	4.77
1987	6.15
1988	7.29
1989	6.34
1991	5.23
1992	4.51
1993	4.13
1994	3.3
1995	4.03
1996	3.94
1997	3.48
1998	3.09
1999	2.6
2000	2.57
2001	3.39
2002	3.03
2003	3.39
2004	3.08
2005	3.77
2006	3.62
2007	2.94
2008	3.23
2009	5.1
2010	4.42
2011	3.76
2012	4.81
2013	4.94
2014	4.54
2015	4.35
2016	4.9
2017	4.65