Year	Percent
1992	0.59667
1993	0.96888
1994	1.70546
1995	2.33657
1996	2.78646
1997	3.6692
1998	4.15408
1999	4.64761
2000	3.66632
2001	2.76487
2002	2.4821
2003	2.54877
2004	2.44947
2005	2.26642
2006	2.46905
2007	2.06324
2008	1.85443
2009	2.22798
2010	2.28045
2011	2.22538
2012	1.72129
2013	1.74265
2014	1.60146
2015	1.68937
2016	1.74566
2017	1.64584