Year	Percent
1991	5.61525
1992	4.25042
1993	2.46452
1994	1.75123
1995	1.9479
1996	1.9036
1997	2.30136
1998	2.32184
1999	3.12403
2000	2.70673
2001	3.00874
2002	2.61785
2003	2.62506
2004	2.52763
2005	2.64514
2006	2.50118
2007	2.61042
2008	3.13724
2009	3.37437
2010	3.51474
2011	3.57459
2012	3.16654
2013	3.0656
2014	4.20412
2015	4.48316
2016	3.84887
2017	3.38227