Year	Percent
1991	74.49
1992	71.412
1993	69.702
1994	67.83
1995	66.907
1996	66.513
1997	66.68
1998	67.647
1999	66.576
2000	66.879
2001	66.786
2002	65.21
2003	65.439
2004	64.781
2005	74.085
2006	72.948
2007	72.302
2008	71.968
2009	71.196
2010	71.725
2011	71.871
2012	71.67
2013	71.092
2014	71.017
2015	71.087
2016	71.482
2017	71.551
2018	71.525
2019	71.491
2020	71.45
2021	71.41
2022	71.371