Year	Percent
1991	54.639
1992	56.677
1993	51.268
1994	47.389
1995	43.909
1996	44.982
1997	41.976
1998	46.01
1999	43.898
2000	46.766
2001	44.556
2002	45.437
2003	47.58
2004	44.655
2005	44.447
2006	41.292
2007	41.421
2008	41.369
2009	39.94
2010	38.422
2011	36.789
2012	35.244
2013	33.885
2014	33.345
2015	32.555
2016	30.053
2017	29.346
2018	28.344
2019	27.485
2020	26.482
2021	25.542
2022	24.653