Year	Percent
1991	10.433
1992	10.036
1993	10.07
1994	9.936
1995	9.704
1996	9.485
1997	8.829
1998	8.073
1999	7.279
2000	6.323
2001	6.34
2002	6.286
2003	6.314
2004	6.155
2005	6.027
2006	5.708
2007	5.637
2008	5.322
2009	5.373
2010	5.246
2011	5.124
2012	4.989
2013	4.91
2014	4.878
2015	4.747
2016	4.661
2017	4.648
2018	4.537
2019	4.425
2020	4.323
2021	4.223
2022	4.129