Year	Percent
1998	10.18
1999	9.44
2000	9.8
2001	9.28
2002	8.22
2003	8.35
2004	8.83
2005	9.29
2006	9.05
2007	10.37
2011	9.95
2012	9.67
2014	10.02
2016	10.84
2017	13.17