Year	per 1,000 people
1960	7.70642185211182
1970	6.53000020980835
1990	6.5999999046
1993	6.1048002243
1996	3.8800001144
2001	2.6
2002	2.3
2003	2.5
2004	2.4
2005	2.4
2006	2.4
2007	2
2008	1.7
2009	2.2
2010	2.2
2013	3.6
2014	3.55
2015	3.61
2016	3.01
2017	2.89