Year	per 1,000 people
1960	6.36363649368286
1970	12.3312997817993
1980	5.09469985961914
1981	4.76830005645752
1990	4.2718000412
1998	1.7999999523
2004	1.5
2005	1.51
2009	1.5
2010	1.4
2011	1.3
2015	1.9
2016	1.86