Year	Percent
1991	3.443
1992	2.999
1993	4.408
1994	3.813
1995	2.3127
1996	2.8988
2003	2.4176
2004	2.555
2005	2.0216
2006	1.7526
2007	0.8933
2008	0.5993
2009	2.1842
2010	3.4349
2011	3.5687
2012	3.864
2013	3.4577
2014	3.0698
2015	3.2814
2016	1.3615
2017	1.5818