Year	Percent
1991	12.346
1992	13.014
1993	13.926
1994	14.475
1995	12.321
1996	12.252
1997	11.768
1998	11.391
1999	11.456
2000	11.107
2001	10.719
2002	10.719
2003	10.408
2004	10.536
2005	10.81
2006	10.727
2007	10.622
2008	10.435
2009	10.713
2010	10.966
2011	10.44
2012	10.475
2013	10.615
2014	10.35
2015	10.275
2016	10.013
2017	9.996
2018	9.934
2019	9.908
2020	9.886
2021	9.864
2022	9.842