Year	Percent
1991	60.221
1992	64.761
1993	66.393
1994	63.871
1995	64.438
1996	63.313
1997	63.097
1998	60.529
1999	59.967
2000	59.801
2001	60.938
2002	61.133
2003	59.802
2004	59.807
2005	59.805
2006	34.995
2007	35.84
2008	28.589
2009	29.072
2010	29.645
2011	29.715
2012	29.963
2013	30.38
2014	29.646
2015	30.526
2016	31.106
2017	31.591
2018	31.556
2019	31.521
2020	31.48
2021	31.44
2022	31.405