Year	Percent
1993	14.23
1994	13.81
1995	13.24
1997	12.84
1998	12.14
1999	11.36
2000	11.52
2001	9.3
2002	10.44
2003	12.17
2004	13.97
2005	12.98
2006	13.13
2007	14.07
2008	14.13
2009	13.22
2010	10.89
2011	10.93
2012	9.77
2013	11.42
2014	11.83
2015	12.63
2016	8.4
2017	8.74