Year	per 1,000 people
1990	5.01
1991	4.873
1999	4.069
2000	4.011
2001	3.936
2002	3.999
2003	4.347
2004	4.37
2005	4.477
2006	4.583
2007	4.715
2008	4.941
2009	5.115
2010	5.335
2011	5.486
2012	5.781
2013	5.778
2014	5.979
2015	6.013
2016	5.324
2017	5.422
2018	5.605