Year % 1996 1.51 2000 1.73 2001 2.64 2003 3.63 2004 2.94 2005 3.32 2006 2.65 2007 2.62 2008 2.82 2009 3.03 2010 3.34 2011 3.68 2012 4.35 2013 5.21 2014 4.85 2015 5.15 2016 6.23 2020 8.33 2021 7.55