Year	Percent
1991	14.115
1992	14.22
1993	13.976
1994	14.523
1995	14.796
1996	15.404
1997	15.52
1998	15.836
1999	15.398
2000	16.399
2001	17.111
2002	16.91
2003	17.408
2004	17.468
2005	16.242
2006	16.259
2007	14.539
2008	13.155
2009	13.156
2010	11.931
2011	10.726
2012	9.97
2013	9.165
2014	8.953
2015	9.946
2016	10.081
2017	10.531
2018	10.649
2019	10.776
2020	10.906
2021	11.038
2022	11.176