Year	Percent
1991	36.117
1992	35.016
1993	34.608
1994	34.981
1995	43.203
1996	46.663
1997	47.749
1998	49.667
1999	52.154
2000	53.417
2001	55.491
2002	57.157
2003	56.897
2004	60.446
2005	61.453
2006	61.392
2007	60.175
2008	59.431
2009	60.374
2010	60.667
2011	61.209
2012	60.061
2013	57.249
2014	56.398
2015	58.06
2016	57.218
2017	56.983
2018	56.651
2019	56.084
2020	55.475
2021	54.86
2022	54.235