Year	Percent
1991	38.919
1992	40.625
1993	37.967
1994	38.802
1995	36.669
1996	39.465
1997	37.812
1998	35.548
1999	46.077
2000	48.431
2001	44.856
2002	41.17
2003	42.887
2004	38.719
2005	38.636
2006	39.237
2007	38.839
2008	38.268
2009	38.771
2010	42.603
2011	41.453
2012	43.624
2013	42.763
2014	42.78
2015	41.644
2016	41.337
2017	41.436
2018	40.829
2019	40.835
2020	40.639
2021	40.575
2022	40.533