Year % 1989 3.44 1990 3.63 1991 3.67 1992 3.63 1993 3.56 1995 3.95 1996 4 1997 2.34 1998 4.07 1999 8.32 2000 5.13 2001 4.58 2002 3.9 2003 3.71 2004 3.63 2005 3.74 2006 3.7 2007 3.71 2008 3.64 2009 3.96 2010 3.95 2011 4.07 2012 4.14 2013 3.98 2014 3.76 2015 3.86 2016 3.88 2017 8.59 2018 8.24 2019 134.84 2020 3.31 2021 2.89