Year	Percent
1991	16.734
1992	16.145
1993	15.808
1994	14.311
1995	14.091
1996	13.962
1997	13.277
1998	13.107
1999	12.558
2000	11.953
2001	11.374
2002	10.806
2003	10.235
2004	9.529
2005	9.382
2006	9.421
2007	9.434
2008	9.41
2009	7.684
2010	7.424
2011	7.514
2012	7.647
2013	7.681
2014	7.937
2015	7.67
2016	7.597
2017	7.534
2018	7.437
2019	7.355
2020	7.278
2021	7.184
2022	7.095