Year	Percent
1991	43.872
1992	43.365
1993	49.176
1994	50.532
1995	46.491
1996	52.502
1997	48.748
1998	46.118
1999	44.361
2000	43.629
2001	44.055
2002	38.355
2003	33.509
2004	34.308
2005	37.602
2006	38.502
2007	43.772
2008	45.251
2009	48.116
2010	49.011
2011	47.725
2012	44.001
2013	46.406
2014	44.669
2015	44.472
2016	42.386
2017	42.902
2018	43.067
2019	43.088
2020	42.713
2021	41.646
2022	40.16