Year	Percent
1991	8.506
1992	8.158
1993	8.783
1994	8.6
1995	8.988
1996	8.345
1997	8.976
1998	9.805
1999	8.736
2000	8.631
2001	9.207
2002	9.228
2003	9.159
2004	9.259
2005	9.203
2006	9.332
2007	9.127
2008	9.436
2009	9.426
2010	9.409
2011	9.214
2012	9.054
2013	9.139
2014	8.463
2015	8.35
2016	8.393
2017	8.494
2018	8.424
2019	8.362
2020	8.287
2021	8.218
2022	8.169