Year	Percent
1991	24.762
1992	23.485
1993	21.522
1994	21.287
1995	20.516
1996	20.13
1997	19.188
1998	19.302
1999	19.307
2000	19.296
2001	18.031
2002	17.867
2003	18.061
2004	17.591
2005	17.086
2006	16.669
2007	16.105
2008	15.384
2009	16.412
2010	14.083
2011	13.652
2012	13.302
2013	12.708
2014	12.779
2015	12.709
2016	12.661
2017	12.76
2018	12.505
2019	12.302
2020	12.109
2021	11.922
2022	11.757