Year	Percent
1991	14.717
1992	15.038
1993	16.128
1994	14.854
1995	14.427
1996	14.871
1997	14.31
1998	13.785
1999	12.573
2000	12.218
2001	12.888
2002	12.019
2003	11.751
2004	12.248
2005	11.474
2006	11.269
2007	10.906
2008	11.367
2009	11.435
2010	10.228
2011	10.444
2012	10.734
2013	10.607
2014	10.706
2015	11.178
2016	11.09
2017	10.993
2018	10.811
2019	10.657
2020	10.565
2021	10.463
2022	10.395