Year	per 1,000 people
2005	5.9
2006	5.54
2007	5.35
2008	5.34
2009	5.35
2010	5.4
2011	5.43
2012	5.44
2013	5.5
2014	5.52
2015	5.58
2016	5.59
2017	5.61