Year % 1990 12.4 1993 12 1996 11.5 1999 10.5 2002 9.6 2005 10 2008 9.4 2010 9.2 2011 9.6 2012 9.7 2013 10.3 2014 10.5 2015 10.6 2016 10.7 2017 10.5 2018 10.7 2019 10.7 2020 11