Year	Percent
1991	82.275
1992	81.759
1993	81.481
1994	81.079
1995	80.702
1996	80.376
1997	80.085
1998	79.775
1999	79.134
2000	78.352
2001	77.768
2002	77.15
2003	76.398
2004	75.613
2005	74.75
2006	73.861
2007	72.95
2008	72.109
2009	71.139
2010	70.218
2011	69.731
2012	69.107
2013	68.403
2014	67.737
2015	67.12
2016	66.559
2017	66.205
2018	65.863
2019	65.576
2020	65.369
2021	65.243
2022	65.193