Year % 2006 5 2007 5.5 2008 5.8 2009 6 2010 5.7 2011 5.5 2012 5.3 2013 5 2014 4.9 2015 5.1 2016 5.6 2017 5.3 2018 5.4 2019 5.7 2020 5.6 2021 6