Year	%
2001	16.75
2002	16.12
2003	17.51
2004	17.36
2005	17.82
2006	18.46
2007	18.61
2008	18.05
2009	18.85
2010	16.98
2011	18.92
2012	17.41
2013	17.3
2015	18.59
2017	17.74
2018	17.03