Year	Percent
1991	43.516
1992	46.218
1993	40.485
1994	41.441
1995	36.732
1996	41.652
1997	38.239
1998	33.792
1999	52.457
2000	53.849
2001	48.226
2002	42.137
2003	43.712
2004	36.768
2005	35.976
2006	36.291
2007	35.098
2008	33.439
2009	33.439
2010	38.683
2011	36.119
2012	38.619
2013	36.738
2014	36.003
2015	33.867
2016	33.294
2017	33.565
2018	32.695
2019	32.814
2020	32.473
2021	32.288
2022	32.046