Year	Percent
1999	15.32
2000	9.75
2001	8.56
2002	7.57
2003	7.17
2004	5.92
2005	5.56
2006	5.06
2007	5.06
2008	4.58
2009	4.66
2010	4.33
2011	4.25
2012	4.09
2013	3.96
2014	3.95
2015	4.02
2016	4.16
2017	4.07
2018	4.07
2019	3.99