Year	per 1,000 people
1960	0.146
1970	0.111
1975	0.113
1980	0.128
1981	0.15
1984	0.154
1985	0.154
1989	0.124
1990	0.119
1992	0.108
1996	1.23
1997	1.24
2000	1.219
2001	1.221
2002	1.112
2003	1.227
2004	1.109
2005	1.23
2006	1.236
2007	1.242
2008	1.251
2009	1.256
2010	1.263
2017	0.669
2018	0.701
2019	0.735
2020	0.752
2021	0.786