Year	Percent
1991	63.41
1992	63.701
1993	67.299
1994	68.666
1995	70.571
1996	70.575
1997	71.074
1998	70.459
1999	71.412
2000	71.891
2001	71.072
2002	71.777
2003	73.962
2004	74.704
2005	76.187
2006	76.529
2007	76.646
2008	76.774
2009	78.063
2010	77.923
2011	77.524
2012	78.136
2013	78.341
2014	78.212
2015	78.416
2016	77.999
2017	78.346
2018	78.918
2019	79.29
2020	79.673
2021	80.061
2022	80.455