Year	Percent
1991	35.399
1992	35.11
1993	33.316
1994	31.438
1995	32.648
1996	32.834
1997	33.981
1998	33.307
1999	33.317
2000	33.276
2001	33.306
2002	34.735
2003	35.178
2004	34.248
2005	35.134
2006	33.845
2007	30.985
2008	30.667
2009	35.387
2010	34.189
2011	32.21
2012	32.129
2013	32.356
2014	32.792
2015	36.05
2016	35.886
2017	35.77
2018	35.55
2019	35.31
2020	35.064
2021	34.827
2022	34.602