Year % 1999 2.54 2001 2.17 2002 1.72 2003 1.2 2004 1.6 2005 1.27 2006 1.07 2007 1.15 2008 1.15 2009 1.46 2010 2.53 2011 2.09 2012 2.13 2013 2.54 2014 3.14 2015 3.34 2016 3.55 2017 3.63 2019 4.13 2020 2.85 2021 3.49