Year	Percent
1991	13.123
1992	13.033
1993	12.92
1994	12.862
1995	12.654
1996	12.391
1997	12.149
1998	11.874
1999	11.628
2000	11.459
2001	11.222
2002	11.084
2003	11.007
2004	10.966
2005	10.936
2006	10.928
2007	10.929
2008	10.94
2009	10.98
2010	11.091
2011	11.147
2012	11.257
2013	11.402
2014	11.557
2015	11.707
2016	11.818
2017	11.866
2018	11.912
2019	11.951
2020	11.977
2021	11.989
2022	11.989