Year	Percent
1991	69.823
1992	70.768
1993	72.502
1994	73.959
1995	74.118
1996	74.315
1997	75.427
1998	75.784
1999	75.921
2000	75.906
2001	76.523
2002	77.605
2003	79.028
2004	80.072
2005	80.498
2006	82.036
2007	82.672
2008	82.795
2009	83.05
2010	83.513
2011	83.227
2012	83.627
2013	82.891
2014	82.432
2015	81.671
2016	81.24
2017	81.518
2018	81.732
2019	81.936
2020	82.129
2021	82.315
2022	82.497