Year	Percent
1991	43.181
1992	42.911
1993	42.42
1994	41.934
1995	42.122
1996	41.593
1997	40.823
1998	40.506
1999	39.9
2000	40.274
2001	40.078
2002	40.102
2003	40.056
2004	40.347
2005	40.404
2006	40.99
2007	41.076
2008	41.303
2009	40.345
2010	40.452
2011	40.627
2012	40.208
2013	39.692
2014	39.02
2015	37.876
2016	37.404
2017	37.125
2018	36.952
2019	36.788
2020	36.646
2021	36.513
2022	36.382