Year	Percent
1991	18.302
1992	17.935
1993	17.322
1994	17.025
1995	16.888
1996	16.335
1997	17.703
1998	19.241
1999	21.287
2000	30.732
2001	32.551
2002	33.072
2003	34.332
2004	35.034
2005	34.991
2006	33.838
2007	33.875
2008	34.095
2009	27.241
2010	27.56
2011	36.687
2012	41.508
2013	43.082
2014	43.088
2015	43.193
2016	43.246
2017	43.176
2018	43.218
2019	43.256
2020	43.295
2021	43.344
2022	43.392