Year	Percent
1991	22.531
1992	20.378
1993	19.646
1994	17.788
1995	16.539
1996	15.755
1997	14.26
1998	13.953
1999	13.732
2000	12.881
2001	12.89
2002	12.717
2003	12.993
2004	13.198
2005	12.757
2006	13.256
2007	12.511
2008	12.066
2009	11.266
2010	11.807
2011	10.479
2012	10.408
2013	10.224
2014	10.099
2015	9.739
2016	9.241
2017	9.178
2018	9.021
2019	8.882
2020	8.735
2021	8.595
2022	8.472