Year per 1,000 uninfected population ages 15-49 1990 0.4 1991 0.6 1992 0.8 1993 1.1 1994 1.4 1995 1.7 1996 1.9 1997 2.1 1998 2.2 1999 2.2 2000 2.2 2001 2.1 2002 2.1 2003 2 2004 1.9 2005 1.8 2006 1.8 2007 1.7 2008 1.6 2009 1.6 2010 1.5 2011 1.5 2012 1.5 2013 1.4 2014 1.4 2015 1.4 2016 1.4 2017 1.3 2018 1.3