Year	Percent
1992	41.2
1993	42.6
1995	48.6
1996	57.4
2002	47.2
2003	37.6
2004	29.4
2005	19
2006	15.2
2007	14.6
2008	8.3
2009	9.8
2010	6.2
2011	5.7
2012	4.1
2013	3.3
2014	3.6
2015	7.8
2016	6.4