Year % 2001 1.55 2003 1.76 2004 2.09 2005 1.92 2006 2.02 2007 2.25 2008 2.44 2009 2.18 2010 2.47 2011 2.89 2012 2.88 2013 2.76 2014 2.87 2015 3.79 2016 2.83 2017 2.56 2019 4.07 2020 3.67 2021 4.02