Year	Percent
1996	41.7
1997	39.4
1998	40.9
1999	39.5
2000	39.1
2001	32.1
2002	31.1
2003	32.5
2004	34.1
2005	33.3
2006	28.8
2007	25.9
2008	26.5
2010	29.96
2011	31.84
2012	30.47
2013	29.69
2016	22.49