Year % 1988 4.28 1990 4.8 1991 5.12 1993 7.31 1996 5.57 1997 2.95 1999 3 2000 2.67 2001 2.42 2002 2.5 2003 2.48 2004 1.87 2005 2.12 2006 2.07 2007 2.06 2008 1.68 2009 1.9 2010 2.06 2011 1.85 2012 1.76 2013 1.7 2014 1.24 2015 2.02 2016 2.58 2017 2.67 2018 1.91 2019 5.68 2020 2.61 2021 2.79