Year	Percent
1991	0.49524
1992	0.47904
1993	0.30546
1994	0.28953
1995	0.64665
1996	0.66063
1997	0.61677
1998	0.61709
1999	0.59933
2000	0.59613
2001	0.59274
2002	0.58065
2003	2.28674
2004	5.78669
2005	3.13326
2006	14.08394
2007	23.03889
2008	22.78584
2009	9.23255
2010	3.23415
2011	6.37538
2012	8.12615
2013	21.58958
2014	10.5151
2015	7.58984
2016	9.06885
2017	8.94473