Year % 1970 7 1975 7.1 1979 7.4 1984 7.5 1990 7.9 1996 7.5 1997 7.6 1998 7.8 1999 7.7 2000 7.6 2001 7.7 2002 8 2003 8.2 2004 8.4 2005 8.6 2006 8.5 2007 8.1 2008 7.9 2009 7.7 2010 7.7 2011 7.8 2012 7.8 2013 8 2014 8 2015 7.9 2016 8 2017 8.1 2018 8 2019 7.8 2020 8 2021 7.7