Year	Percent
1991	57.523
1992	62.955
1993	63.508
1994	63.176
1995	64.67
1996	64.582
1997	64.523
1998	60.378
1999	62.453
2000	62.919
2001	63.253
2002	64.995
2003	65.325
2004	67.709
2005	68.477
2006	68.83
2007	69.529
2008	71.331
2009	72.306
2010	73.136
2011	75.41
2012	76.272
2013	77.359
2014	78.72
2015	79.375
2016	80.069
2017	79.788
2018	80.276
2019	80.718
2020	81.081
2021	81.463
2022	81.718