Year	Percent
1990	5.57
1991	5.59
1992	5.6
1993	5.62
1994	5.63
1995	5.65
1996	5.66
1997	5.68
1998	5.69
1999	5.71
2000	5.73
2001	5.89
2002	6.06
2003	6.23
2004	6.4
2005	6.56
2006	6.56
2007	6.56
2008	6.56
2009	6.56
2010	6.56
2011	6.56
2012	6.56
2013	6.56
2014	6.56
2015	6.56