Year	Percent
1992	0.57362
1993	1.14456
1994	1.66116
1995	2.08446
1996	2.05467
1997	1.94663
1998	1.33546
1999	1.5283
2000	1.02543
2001	0.90352
2002	1.15744
2003	1.66309
2004	2.05592
2005	2.4882
2006	2.56699
2007	2.44401
2008	2.33809
2009	3.03401
2010	3.80851
2011	4.47598
2012	5.86867
2013	6.44333
2014	5.42214
2015	4.62951
2016	4.13491
2017	2.99748