Year	per 1,000 uninfected population
1990	4.59
1991	6.33
1992	8.27
1993	10.42
1994	12.25
1995	13.57
1996	14.07
1997	13.71
1998	13.04
1999	12.25
2000	11.46
2001	10.78
2002	10.18
2003	9.69
2004	9.11
2005	8.59
2006	7.59
2007	6.67
2008	6.14
2009	5.91
2010	5.68
2011	5.34
2012	5.27
2013	4.87
2014	4.51
2015	4.25
2016	4.13
2017	3.85
2018	3.53
2019	3.18
2020	2.74
2021	2.71
2022	2.39