Year	Percent
1991	41.761
1992	41.665
1993	41.585
1994	40.848
1995	40.738
1996	40.956
1997	40.86
1998	39.845
1999	38.694
2000	37.461
2001	37.102
2002	36.939
2003	37.643
2004	38.917
2005	39.807
2006	40.299
2007	40.217
2008	41.155
2009	41.823
2010	40.508
2011	38.503
2012	37.437
2013	37.136
2014	38.013
2015	39.048
2016	39.275
2017	40.073
2018	41.033
2019	41.282
2020	41.224
2021	41.151
2022	41.055