Year	Percent
1991	50.63
1992	44.612
1993	37.992
1994	35.128
1995	34.628
1996	33.127
1997	33.481
1998	34.18
1999	33.881
2000	30.305
2001	34.192
2002	31.166
2003	28.738
2004	25.937
2005	23.161
2006	18.068
2007	14.465
2008	12.088
2009	8.3
2010	6.904
2011	5.781
2012	4.959
2013	4.483
2014	5.096
2015	6.575
2016	7.035
2017	9.443
2018	9.182
2019	8.984
2020	8.878
2021	8.779
2022	8.681