Year	Percent
1978	1.11
1979	1.13
1980	0.86
1982	0.6
1983	0.53
1984	1.51
1986	3.53
1987	2.46
1988	0.79
1989	0.69
1991	1.2
1992	1.67
1993	1.57
1994	2.7
1995	1.38
1996	2.73
1997	1.14
1998	2.18
1999	4.83
2001	2.29
2002	3.78
2003	2.97
2004	3.18
2006	4.03
2007	3.25
2008	3.09
2009	4.76
2010	2.63
2011	3.14
2012	3.12
2013	2.99
2014	2.84
2015	3.02
2016	3.52