Year	Percent
1996	17.79
1997	13.81
1998	13.06
1999	13.16
2000	14.12
2001	12.84
2002	12.96
2003	11.21
2004	10.66
2005	9.53
2006	6.16
2007	5.71
2008	7.36
2009	16.2
2010	18.03
2011	14.84
2012	13.7
2013	11.05
2014	10.35
2015	9.54
2016	9.29
2017	8.25
2018	7.16
2019	5.93
2020	7.94