Year	Percent
1991	1.638
1992	1.333
1993	1.134
1994	0.962
1995	0.828
1996	0.743
1997	0.636
1998	0.57
1999	0.467
2000	0.392
2001	0.342
2002	0.339
2003	0.312
2004	0.326
2005	0.329
2006	0.314
2007	0.318
2008	0.338
2009	0.344
2010	0.362
2011	0.372
2012	0.394
2013	0.435
2014	0.446
2015	0.47
2016	0.479
2017	0.419
2018	0.411
2019	0.395
2020	0.384
2021	0.373
2022	0.374