Year	per 1,000 people
1960	0.608832836151123
1970	0.784300029277802
1975	0.776000022888184
1980	0.740499973297119
1985	0.723100006580353
1990	0.7555999756
1993	0.7990999818
1996	0.7099999785
2000	0.7
2007	1.3
2013	0.71