Year	Percent
1991	5.24
1992	5.039
1993	4.857
1994	6.479
1995	9.196
1996	7.589
1997	5.641
1998	5.154
1999	2.947
2000	4.434
2001	3.806
2002	4.954
2003	5.6072
2004	6.363
2005	6.1741
2006	6.4074
2007	6.5529
2008	7.024
2009	9.4118
2010	9.2965
2011	9.2487
2012	8.8502
2013	8.6775
2014	8.737
2015	7.7743
2016	7.097
2017	6.27