Year	Percent
1991	76.391
1992	76.514
1993	77.329
1994	76.881
1995	77.044
1996	76.388
1997	75.765
1998	71.695
1999	72.661
2000	72.443
2001	70.792
2002	70.524
2003	70.596
2004	69.629
2005	69.409
2006	68.904
2007	68.633
2008	69.402
2009	61.234
2010	52.948
2011	43.228
2012	33.625
2013	32.585
2014	30.896
2015	29.281
2016	27.937
2017	27.219
2018	26.252
2019	25.267
2020	24.31
2021	23.346
2022	22.535