Year % 2000 22 2001 22.7 2002 22.4 2003 19.6 2004 20.1 2005 21.3 2006 21.2 2007 22.4 2008 22.1 2009 22 2010 21.4 2011 21.1 2012 21.8 2013 21.5 2014 21.6 2015 21.1 2016 21.1 2017 21.4 2018 21.1 2019 21