Year	Percent
1991	66.604
1992	67.263
1993	66.847
1994	66.84
1995	68.01
1996	67.342
1997	66.971
1998	67.216
1999	67.311
2000	66.296
2001	65.53
2002	60.014
2003	59.151
2004	57.87
2005	57.632
2006	57.389
2007	57.096
2008	57.594
2009	35.57
2010	35.778
2011	35.188
2012	35.281
2013	35.506
2014	35.706
2015	35.754
2016	35.352
2017	35.497
2018	35.482
2019	35.468
2020	35.453
2021	35.438
2022	35.423