Year	Percent
1991	23.266
1992	29.744
1993	34.864
1994	38.115
1995	29.412
1996	27.807
1997	25.016
1998	23.219
1999	23.347
2000	22.04
2001	20.891
2002	21.637
2003	22.875
2004	23.141
2005	24.344
2006	21.272
2007	19.081
2008	19.222
2009	19.075
2010	21.231
2011	21.018
2012	18.109
2013	15.479
2014	12.376
2015	12.35
2016	10.574
2017	10.449
2018	10.413
2019	10.385
2020	10.355
2021	10.337
2022	10.326