Year	Percent
1991	0.346
1992	0.373
1993	0.336
1994	0.348
1995	0.358
1996	0.333
1997	0.336
1998	0.359
1999	0.395
2000	0.398
2001	0.382
2002	0.343
2003	0.342
2004	0.333
2005	0.321
2006	0.322
2007	0.315
2008	0.309
2009	0.303
2010	0.31
2011	0.32
2012	0.344
2013	0.357
2014	0.369
2015	0.36
2016	0.358
2017	0.359
2018	0.365
2019	0.38
2020	0.393
2021	0.412
2022	0.407