Year	Percent
1980	0.56
1981	0.38
1982	0.25
1983	0.61
1984	0.36
1985	0.23
1986	0.32
1987	0.29
1988	0.27
1989	0.17
1990	0.16
1991	0
1992	0
1993	0.16
1994	0.14
1995	0.14
1996	0.25
1997	0.46
1998	1.66
1999	0.97
2000	0.63
2001	0.47
2002	0.5
2003	0.43
2004	0.64
2005	0.67
2006	0.63
2007	0.61
2008	0.75
2009	0.94
2010	1.94
2011	1.62
2012	1.6
2013	1.11
2014	1.56
2015	2.25
2016	2.24
2017	2.69
2018	2.89
2019	3.29
2020	3.62