Year	Percent
1991	32.551
1992	33.738
1993	33.606
1994	32.79
1995	33.017
1996	33.128
1997	33.558
1998	33.463
1999	33.481
2000	33.387
2001	32.91
2002	33.214
2003	32.375
2004	32.407
2005	33.453
2006	34.443
2007	34.235
2008	32.459
2009	29.039
2010	33.111
2011	32.066
2012	32.991
2013	29.297
2014	32.522
2015	32.471
2016	33.543
2017	33.368
2018	33.14
2019	32.926
2020	32.733
2021	32.587
2022	32.48