Year	Percent
1991	46.119
1992	47.633
1993	52.294
1994	49.004
1995	48.402
1996	48.061
1997	46.414
1998	45.38
1999	45.683
2000	45.856
2001	46.928
2002	47.593
2003	46.2
2004	46.126
2005	47.082
2006	46.166
2007	45.831
2008	47.102
2009	44.527
2010	43.613
2011	42.366
2012	45.647
2013	44.438
2014	44.474
2015	43.845
2016	43.368
2017	42.155
2018	41.225
2019	40.339
2020	39.551
2021	38.821
2022	38.107