Year	Percent
1991	22.983
1992	21.984
1993	20.906
1994	20.452
1995	20.114
1996	19.496
1997	19.305
1998	19.1
1999	19.018
2000	18.455
2001	17.832
2002	17.373
2003	17.116
2004	16.916
2005	16.629
2006	15.72
2007	15.316
2008	14.91
2009	14.633
2010	14.296
2011	13.842
2012	11.851
2013	11.621
2014	11.516
2015	11.143
2016	10.644
2017	11.01
2018	10.69
2019	10.59
2020	10.483
2021	10.427
2022	10.292