Year	Percent
1991	20.625
1992	19.669
1993	18.516
1994	17.189
1995	17.513
1996	15.579
1997	14.602
1998	14.229
1999	14
2000	14.16
2001	13.801
2002	12.959
2003	13.069
2004	13.292
2005	12.899
2006	13.413
2007	12.978
2008	12.262
2009	11.417
2010	11.471
2011	12.45
2012	12.656
2013	13.005
2014	12.695
2015	12.14
2016	11.984
2017	12.007
2018	11.844
2019	11.672
2020	11.523
2021	11.388
2022	11.274