Year	Percent
1978	0.6
1979	0.57
1980	0.56
1981	0.18
1982	0.68
1983	0.95
1984	0.91
1985	1.03
1986	0.86
1987	0.55
1988	0.41
1989	0.4
1990	0.28
1991	0.41
1992	0.27
1993	0.41
1994	0.41
1995	0.41
1996	0.82
1997	1.08
1998	0.96
1999	1.13
2000	1.31
2001	1.97
2002	2.26
2003	3.24
2004	2.68
2005	2.55
2006	2.03
2007	1.71
2008	2.11
2009	3
2010	2.58
2011	2.22
2012	2
2013	1.9
2014	1.7
2015	1.5
2016	1.78
2017	1.68
2018	1.77
2019	1.8
2020	2.22