Year	Percent
1991	45.839
1992	41.389
1993	37.613
1994	35.622
1995	32.573
1996	30.823
1997	32.837
1998	38.252
1999	37.033
2000	34.975
2001	36.392
2002	36.668
2003	34.435
2004	31.942
2005	30.904
2006	30.934
2007	30.539
2008	30.782
2009	29.506
2010	26.126
2011	24.421
2012	20.993
2013	20.174
2014	21.686
2015	21.597
2016	22.555
2017	23.562
2018	25.033
2019	25.7
2020	25.847
2021	25.909
2022	25.921