Year	Percent
1980	0.864
1981	0.598
1982	0.392
1983	0.777
1984	0.595
1985	0.375
1986	0.547
1987	0.337
1988	0.319
1989	0.311
1990	0.291
1991	0
1992	0
1993	0.272
1994	0.258
1995	0.248
1996	0.235
1997	0.652
1998	2.146
1999	1.004
2000	0.9
2001	0.7
2002	0.8
2003	0.7
2004	1
2005	1
2006	1
2007	0.9
2008	1.1
2009	1.6
2010	2.7
2011	2.5
2012	2.3
2013	1.6
2014	2.2
2015	2.6
2016	2.5
2017	3