Year	per 1,000 people
1999	4.02
2001	4.222
2004	4.526
2005	4.642
2006	4.664
2007	4.789
2008	5.004
2009	5.347
2010	5.682
2011	5.105
2012	5.466
2013	5.548
2014	5.699
2015	5.948
2016	6.105
2017	6.182