Year	Percent
1991	2.888
1992	4.897
1993	5.601
1994	5.542
1995	4.905
1996	3.4501
1997	3.8184
1998	3.8036
1999	2.7895
2000	2.6252
2001	2.2398
2002	2.6479
2003	3.969
2004	2.7511
2005	2.4906
2006	3.0598
2007	2.268
2008	2.5812
2009	5.6831
2010	6.7366
2011	6.2114
2012	5.6649
2013	5.0767
2014	4.7858
2015	4.0505
2016	3.046
2017	2.7176