Year % 1992 5.15 1997 4.9 2001 4.95 2002 7.66 2003 4.7 2004 4.85 2005 3.8 2006 3.88 2007 3.67 2008 3.85 2009 3.57 2012 3.52 2013 3.39 2014 3.33 2015 3.29 2016 3.18 2017 3.36 2018 3.36 2019 3.16 2020 3.15 2021 2.99