Year	Percent
1978	1.44
1979	0.8
1980	1.37
1982	0.74
1983	1.25
1984	2.14
1985	3.12
1986	5.8
1987	3.72
1988	2.38
1989	1.4
1991	1.34
1992	1.31
1993	1.74
1994	1.96
1995	1.68
1996	3.04
1997	2.31
1998	2.82
1999	4.36
2001	3.44
2002	5.94
2003	5.53
2004	5.88
2006	4.83
2007	4.44
2008	3.75
2009	5.94
2010	3.44
2011	3.63
2012	3.06
2013	3.32
2014	3.05
2015	3.67
2016	3.5