Year	Percent
1991	15.338
1992	15.159
1993	14.236
1994	14.191
1995	13.727
1996	13.296
1997	13.035
1998	12.571
1999	12.261
2000	11.49
2001	10.969
2002	10.842
2003	11.577
2004	11.121
2005	10.972
2006	11.457
2007	11.078
2008	10.648
2009	11.042
2010	11.592
2011	11.727
2012	11.541
2013	11.368
2014	11.698
2015	11.691
2016	11.915
2017	11.816
2018	11.762
2019	11.714
2020	11.668
2021	11.623
2022	11.585