Year	Percent
1993	21.72
1999	13.35
2000	11.42
2001	11.5
2002	12.93
2003	12.9
2004	12.92
2005	11.89
2006	9.68
2007	9.03
2008	8.03
2009	8.62
2010	7.73
2011	6.85
2012	6.1
2013	6.82
2014	7.25
2015	7.62
2016	6.96