Year	Percent
1991	41.998
1992	42.487
1993	42.416
1994	42.616
1995	42.646
1996	40.839
1997	41.098
1998	41.38
1999	41.503
2000	41.757
2001	41.866
2002	41.841
2003	41.876
2004	42.017
2005	41.861
2006	41.745
2007	41.617
2008	41.503
2009	41.444
2010	41.363
2011	41.267
2012	41.117
2013	40.927
2014	40.762
2015	40.642
2016	40.501
2017	40.482
2018	40.416
2019	40.31
2020	40.153
2021	39.966
2022	39.74