Year	Percent
1991	60.159
1992	54.162
1993	57.368
1994	56.258
1995	51.878
1996	51.316
1997	52.207
1998	54.389
1999	54.09
2000	56.128
2001	57.943
2002	60.02
2003	58.076
2004	67.87
2005	64.295
2006	60.866
2007	59.219
2008	60.647
2009	59.42
2010	53.046
2011	53.106
2012	50.424
2013	48.164
2014	47.286
2015	48.363
2016	45.643
2017	45.642
2018	45.617
2019	45.578
2020	45.538
2021	45.496
2022	45.455