Year	Percent
1991	16.958
1992	16.705
1993	16.045
1994	15.554
1995	15.337
1996	14.724
1997	14.266
1998	13.871
1999	12.884
2000	12.745
2001	12.253
2002	11.947
2003	11.605
2004	10.955
2005	10.56
2006	10.437
2007	9.916
2008	9.66
2009	9.329
2010	9.052
2011	8.349
2012	8.198
2013	8.842
2014	8.757
2015	8.652
2016	7.899
2017	7.973
2018	7.757
2019	7.55
2020	7.351
2021	7.177
2022	6.997