Year	Percent
1996	33.7
1997	33.6
1998	35.3
1999	36.3
2000	34.4
2001	28
2002	26
2003	29.5
2004	30.7
2005	26.6
2006	26.5
2007	22.9
2008	22.8
2010	27.97
2011	27.47
2012	26.8
2013	28.29
2016	22.29