Year	Percent
1991	35.525
1992	33.176
1993	33.172
1994	34.243
1995	35.004
1996	34.373
1997	36.648
1998	40.797
1999	43.562
2000	43.797
2001	42.482
2002	41.732
2003	42.396
2004	41.519
2005	45.973
2006	46.455
2007	47.757
2008	44.892
2009	38.807
2010	33.808
2011	31.797
2012	30.834
2013	30.524
2014	29.541
2015	29.521
2016	33.385
2017	34.01
2018	33.877
2019	33.437
2020	33.121
2021	32.879
2022	32.671