Year	Percent
1991	9.806
1992	9.182
1993	8.541
1994	7.918
1995	7.47
1996	6.945
1997	6.491
1998	6.04
1999	5.581
2000	5.218
2001	5.06
2002	4.959
2003	4.904
2004	4.455
2005	4.008
2006	3.697
2007	3.708
2008	3.58
2009	3.601
2010	3.577
2011	3.294
2012	3.115
2013	3.109
2014	3.172
2015	3.039
2016	3.02
2017	2.919
2018	2.832
2019	2.746
2020	2.677
2021	2.612
2022	2.554