Year	Percent
1991	42.45
1992	40.499
1993	39.612
1994	40.218
1995	36.516
1996	35.713
1997	35.122
1998	34.795
1999	34.479
2000	36.261
2001	34.257
2002	35.688
2003	34.706
2004	34.48
2005	35.555
2006	34.166
2007	32.491
2008	32.891
2009	31.68
2010	31.927
2011	30.83
2012	28.8
2013	27.942
2014	27.549
2015	26.66
2016	26.38
2017	26.002
2018	25.739
2019	25.482
2020	25.253
2021	25.038
2022	24.828