Year	Percent
1991	16.284
1992	17.376
1993	14.661
1994	13.974
1995	14.072
1996	12.765
1997	12.552
1998	11.691
1999	11.285
2000	10.536
2001	10.326
2002	10.092
2003	9.264
2004	10.347
2005	9.83
2006	9.115
2007	9.247
2008	8.584
2009	9.202
2010	8.965
2011	8.569
2012	8.742
2013	8.255
2014	7.852
2015	8.031
2016	8.209
2017	8.388
2018	8.395
2019	8.352
2020	8.336
2021	8.319
2022	8.302