Year % 1981 5.4 1988 6.1 1990 5.9 1992 5.4 1994 6.1 1996 6.2 1998 6.4 1999 6.1 2000 6.2 2002 6.3 2004 6.1 2006 6 2007 6.5 2008 6.4 2009 6.5 2010 6.6 2011 7.2 2012 6.6 2013 6.9 2014 7.1 2015 7.5 2016 7.3 2017 7.3 2018 7.2 2019 7.7 2020 7.5 2021 7.6