Year	%
2000	17.4
2001	17.1
2002	17.9
2003	18.1
2004	17
2005	18.2
2006	18.8
2007	19.1
2008	19.5
2009	19
2014	16.6
2015	16.2
2016	15.7
2017	16.1
2019	16.1