Year	Percent
1991	14.741
1992	14.514
1993	16.176
1994	16.13
1995	15.766
1996	15.431
1997	16.094
1998	15.532
1999	15.181
2000	15.345
2001	15.478
2002	14.96
2003	14.925
2004	15.034
2005	14.875
2006	15.167
2007	14.507
2008	13.773
2009	13.072
2010	13.389
2011	13.056
2012	12.263
2013	11.055
2014	10.901
2015	10.418
2016	10.376
2017	10.441
2018	10.418
2019	10.132
2020	9.981
2021	9.914
2022	9.826