Year	Percent
1991	33.708
1992	34.024
1993	33.529
1994	34.557
1995	34.336
1996	34.621
1997	34.671
1998	33.05
1999	32.985
2000	34.052
2001	33.238
2002	31.486
2003	32.031
2004	31.477
2005	32.12
2006	32.892
2007	33.284
2008	33.555
2009	33.945
2010	34.251
2011	34.102
2012	33.982
2013	33.81
2014	33.55
2015	33.015
2016	33.617
2017	31.106
2018	31.388
2019	31.676
2020	31.983
2021	32.236
2022	32.448