Year	Percent
1991	10.309
1992	10.134
1993	9.893
1994	9.165
1995	8.365
1996	7.545
1997	7.173
1998	7.1
1999	7.021
2000	6.546
2001	6.583
2002	6.956
2003	7.482
2004	7.642
2005	7.681
2006	7.361
2007	7.254
2008	7.064
2009	6.213
2010	5.897
2011	6.388
2012	6.278
2013	6.495
2014	6.739
2015	6.631
2016	6.949
2017	7.226
2018	7.156
2019	7.161
2020	7.061
2021	6.933
2022	6.77