Year	per 1000 people
1960	0.418
1965	0.262
1970	0.445
1975	0.454
1980	0.726
1981	0.673
1984	1.043
1990	0.72
1991	0.732
1993	0.658
1994	0.788
1995	0.943
1996	0.761
1997	0.753
1998	0.939
1999	0.926
2000	1.006
2001	0.97
2002	0.825
2003	0.808
2006	1.222
2007	1.179
2009	1.507
2010	1.809
2011	1.821