Year	per 1,000 people
1960	1.87069153785706
1970	2.34910011291504
1975	2.54629993438721
1980	1.90719997882843
1990	1.6440999508
1993	1.6000000238
1996	1.5499999523
2002	1.5
2003	1.7
2007	1.5
2008	1.5
2009	1.6
2010	1.59
2011	1.62
2012	1.5
2013	1.51
2014	1.55
2015	1.57
2016	1.39