Year	Percent
1991	7.584
1992	7.346
1993	7.331
1994	6.791
1995	6.799
1996	6.854
1997	6.756
1998	6.746
1999	6.716
2000	6.727
2001	6.768
2002	6.809
2003	6.841
2004	6.887
2005	6.925
2006	6.911
2007	6.933
2008	6.926
2009	6.95
2010	6.976
2011	6.985
2012	6.988
2013	6.981
2014	6.996
2015	7.046
2016	7.093
2017	7.086
2018	7.098
2019	7.113
2020	7.138
2021	7.163
2022	7.21