Year	per 1000 people
1960	0.312
1970	0.224
1975	0.218
1983	0.407
1985	0.445
1993	1.027
1996	1.324
2004	1.385
2005	1.172
2006	0.834
2007	1.002
2008	0.764
2009	1.115
2010	1.074
2011	1.141
2012	0.984