Year	Percent
1978	1.39
1979	0.85
1980	1.28
1982	0.71
1983	1.12
1984	2.02
1986	5.37
1987	3.45
1988	1.7
1989	0.93
1991	0.79
1992	1.39
1993	1.7
1994	2.15
1995	1.61
1996	2.96
1997	2
1998	2.75
1999	4.42
2001	3.08
2002	5.25
2003	4.54
2004	5.08
2006	4.51
2007	4.02
2008	3.52
2009	5.52
2010	3.21
2011	3.41
2012	3.08
2013	3.13
2014	2.96
2015	3.44
2016	3.45