Year	Percent
1991	33.286
1992	33.227
1993	33.357
1994	33.551
1995	33.774
1996	33.97
1997	34.095
1998	34.221
1999	34.462
2000	34.574
2001	34.712
2002	34.849
2003	35.054
2004	35.173
2005	35.424
2006	35.486
2007	35.596
2008	35.579
2009	35.194
2010	35.142
2011	35.133
2012	35.235
2013	35.252
2014	35.312
2015	35.355
2016	35.308
2017	35.212
2018	35.156
2019	35.092
2020	35.056
2021	35.025
2022	34.999