Year	Percent
1991	44.17
1992	43.663
1993	43.341
1994	43.361
1995	35.364
1996	35.11
1997	34.861
1998	35.583
1999	35.405
2000	36.071
2001	34.821
2002	28.266
2003	28.16
2004	27.483
2005	37.47
2006	36.699
2007	36.012
2008	35.475
2009	35.989
2010	35.847
2011	36.989
2012	36.95
2013	35.95
2014	34.018
2015	29.607
2016	29.842
2017	29.826
2018	29.785
2019	29.734
2020	29.683
2021	29.633
2022	29.586