Year	Percent
1991	10.2
1992	10.037
1993	10.036
1994	9.643
1995	9.799
1996	8.86
1997	8.425
1998	8.455
1999	8.544
2000	8.547
2001	8.434
2002	8.428
2003	8.386
2004	8.35
2005	8.554
2006	8.553
2007	8.571
2008	8.634
2009	8.68
2010	8.69
2011	8.639
2012	8.531
2013	9.674
2014	9.579
2015	9.416
2016	9.353
2017	9.392
2018	9.363
2019	9.332
2020	9.3
2021	9.273
2022	9.244