Year	Percent
1991	20.462
1992	22.101
1993	19.738
1994	19.456
1995	19.858
1996	17.903
1997	17.516
1998	16.059
1999	15.736
2000	15.257
2001	14.689
2002	13.827
2003	13.365
2004	14.489
2005	13.74
2006	12.757
2007	12.505
2008	12.251
2009	12.659
2010	12.355
2011	12.181
2012	11.763
2013	11.305
2014	11.016
2015	10.895
2016	10.773
2017	11.064
2018	11.071
2019	11.016
2020	10.992
2021	10.968
2022	10.944