Year	Percent
1991	13.606
1992	13.342
1993	12.729
1994	12.672
1995	12.493
1996	12.535
1997	12.516
1998	12.307
1999	11.945
2000	12.174
2001	11.337
2002	10.447
2003	10.177
2004	9.952
2005	9.678
2006	9.536
2007	9.508
2008	9.059
2009	8.147
2010	7.916
2011	8.206
2012	8.236
2013	8.253
2014	8.407
2015	8.382
2016	8.251
2017	8.347
2018	8.261
2019	8.124
2020	8.041
2021	7.967
2022	7.9