Year % 1997 12.8 2000 10.83 2001 10.6 2002 7.68 2003 7.57 2004 6.97 2005 6.51 2006 6.36 2007 5.21 2008 3.24 2009 5.29 2010 4.95 2011 1.76 2012 1.68 2013 1.87 2014 2.02 2015 1.95 2016 1.82 2017 1.26 2018 1.99 2019 1.99 2020 2.21 2021 2.28