Year	Percent
1991	14.928
1992	12.267
1993	11.725
1994	10.943
1995	10.267
1996	9.776
1997	9.41
1998	10.51
1999	10.236
2000	9.473
2001	9.019
2002	8.403
2003	7.895
2004	7.285
2005	7.255
2006	7.053
2007	6.73
2008	6.65
2009	6.636
2010	6.359
2011	6.076
2012	6.049
2013	5.977
2014	5.643
2015	5.188
2016	4.958
2017	4.949
2018	4.866
2019	4.789
2020	4.714
2021	4.643
2022	4.578