Year	Percent
1976	5.76
1977	5.07
1978	3.13
1979	3.13
1980	2.21
1981	2.14
1982	1.99
1983	2.06
1984	2.8
1985	4.32
1986	5.83
1987	4.32
1988	2.77
1989	2.05
1991	2.21
1992	3.18
1993	3.41
1994	3.45
1995	3.45
1996	3.87
1997	2.6
1998	3.68
1999	5.21
2000	3.5
2001	3.89
2002	5.78
2003	6.21
2004	6.19
2006	4.94
2007	4.36
2008	4.38
2009	6.51
2010	4.4
2011	4.32
2012	4.2
2013	4.38
2014	4.09
2015	3.96
2016	4.48