Year	Percent
1991	30.282
1992	34.882
1993	35.849
1994	35.46
1995	34.555
1996	34.185
1997	30.326
1998	29.15
1999	29.063
2000	29.321
2001	29.745
2002	30.597
2003	29.769
2004	28.767
2005	27.921
2006	26.602
2007	25.546
2008	24.985
2009	24.937
2010	25.331
2011	25.323
2012	24.997
2013	24.567
2014	24.297
2015	24.183
2016	23.892
2017	24.477
2018	24.375
2019	24.306
2020	24.263
2021	24.242
2022	24.22