Year	Percent
1991	14.591
1992	14.55
1993	15.15
1994	15.316
1995	14.792
1996	14.844
1997	14.125
1998	12.985
1999	12.305
2000	11.893
2001	11.567
2002	11.01
2003	10.77
2004	10.967
2005	10.439
2006	9.967
2007	10.043
2008	10.638
2009	9.665
2010	9.45
2011	9.23
2012	8.492
2013	8.486
2014	8.188
2015	8.06
2016	7.833
2017	7.801
2018	7.672
2019	7.512
2020	7.34
2021	7.193
2022	7.064