Year	Percent
1991	7.3
2002	12.77
2003	11.85
2004	12.15
2005	10.9
2006	9.86
2007	8.69
2008	7.25
2009	7.97
2010	10.17
2011	12.43
2012	14.54
2013	15.47
2014	15.27
2015	14.39
2016	11.64
2017	10.1
2018	7.67
2019	6.29
2020	6.77