Year	Percent
1991	10.83686
1992	10.7492
1993	10.66268
1994	11.57323
1995	10.44252
1996	10.23284
1997	12.14354
1998	12.06963
1999	10.84421
2000	9.60152
2001	9.9438
2002	9.65957
2003	8.43568
2004	9.77798
2005	9.11275
2006	9.58634
2007	9.8887
2008	8.5904
2009	9.12201
2010	8.8176
2011	8.59837
2012	8.39366
2013	8.5016
2014	9.62722
2015	7.07766
2016	5.02425
2017	5.56243
2018	5.48149
2019	4.28131