Year	Percent
1991	48.536
1992	47.214
1993	47.335
1994	43.891
1995	43.127
1996	41.506
1997	41.122
1998	41.366
1999	41.88
2000	42.268
2001	41.447
2002	41.568
2003	41.667
2004	37.774
2005	39.657
2006	40.362
2007	39.2
2008	37.949
2009	36.591
2010	36.465
2011	37.744
2012	37.766
2013	37.16
2014	37.246
2015	37.791
2016	37.588
2017	37.68
2018	37.584
2019	37.402
2020	37.205
2021	37.026
2022	36.882