Year	Percent
1991	25.789
1992	23.548
1993	22.009
1994	21.04
1995	20.211
1996	19.428
1997	18.894
1998	18.899
1999	18.491
2000	18.28
2001	17.88
2002	17.616
2003	16.922
2004	17.009
2005	16.017
2006	16.015
2007	15.954
2008	15.01
2009	14.564
2010	14.268
2011	14.191
2012	14.16
2013	14.012
2014	14.17
2015	13.868
2016	13.808
2017	13.67
2018	13.435
2019	13.214
2020	13.065
2021	12.91
2022	12.769