Year	Percent
1991	62.731
1992	65.125
1993	70.633
1994	76.238
1995	76.127
1996	73.794
1997	75.464
1998	77.003
1999	78.413
2000	79.783
2001	81.206
2002	79.988
2003	76.147
2004	76.587
2005	76.477
2006	75.804
2007	74.979
2008	74.363
2009	72.45
2010	70.632
2011	70.068
2012	69.084
2013	68.58
2014	68.737
2015	69.221
2016	69.419
2017	69.497
2018	69.477
2019	69.446
2020	69.413
2021	69.361
2022	69.308