Year	Percent
1992	0.63097
1993	0.99542
1994	1.60428
1995	2.18295
1996	2.53046
1997	3.30361
1998	3.74049
1999	4.29321
2000	3.42664
2001	2.5431
2002	2.24838
2003	2.34456
2004	2.27163
2005	2.12762
2006	2.22684
2007	1.85198
2008	1.72069
2009	1.97156
2010	1.98965
2011	1.94248
2012	1.50292
2013	1.53659
2014	1.41445
2015	1.51546
2016	1.60126
2017	1.50187