Year	per 1000 people
1970	2.4
1971	1.958
1972	2.208
1973	2.25
1974	2.375
1975	2.36
1976	2.417
1977	2.4
1978	2.32
1979	2.36
1980	2.385
1981	2.231
1982	2.185
1989	2.857
1992	3
1995	5.81
2011	6.722
2012	6.791
2013	6.661
2014	6.645