Year	Percent
1991	4.47
1992	4.11
1993	3.2
1994	3.37
1995	3.93
1996	3.59
1997	3.18
1998	3.44
1999	3.01
2000	3.03
2001	3.45
2002	2.51
2003	2.22
2004	2.38
2005	2.49
2006	2.17
2007	2.16
2008	2.12
2011	1.46
2012	1.47