Year	Percent
1991	55.433
1992	52.74
1993	49.546
1994	48.08
1995	46.076
1996	43.175
1997	42.805
1998	43.328
1999	44.284
2000	44.052
2001	44.352
2002	43.546
2003	42.731
2004	39.782
2005	40.302
2006	41.963
2007	43.944
2008	44.961
2009	44.573
2010	44.454
2011	45.713
2012	44.267
2013	44.985
2014	44.261
2015	44.182
2016	44.739
2017	44.941
2018	45.15
2019	45.404
2020	45.523
2021	45.569
2022	45.595