Year	per 1,000 people
1960	4.71666669845581
1970	3.95160007476807
1975	3.29970002174377
1980	3.12220001220703
1985	3.34649991989136
1991	2.8866000175
1992	3.1350998878
1993	3.0947999954
1994	3.0745999813
2005	3
2008	3.3
2011	3.4