Year	per 1,000 people
1980	0.699999988079071
1990	1
1991	1.1000000238
1992	1.2000000477
1993	1.2000000477
1994	1.2000000477
1995	1.2000000477
1996	1.2000000477
1997	1.1000000238
1998	1.1000000238
1999	1.1000000238
2000	1.05
2001	1.08
2002	1.09
2003	1.06
2004	1.07
2005	1.05
2006	1.02
2007	1.06
2008	1.03
2009	1.02
2010	1.05
2011	1.04
2012	1.03
2013	1.03
2014	1.03
2015	1
2016	1
2017	0.99
2018	0.98