Year % 1997 6.62768031189084 1998 6.62768031189084 1999 5.65302144249513 2000 5.65302144249513 2001 6.82261208576998 2002 6.23781676413255 2003 8.57699805068226 2004 8.57699805068226 2005 8.57699805068226 2006 8.7719298245614 2007 8.96686159844054 2008 8.96686159844054 2009 8.7719298245614 2010 8.57699805068226 2011 8.57699805068226 2012 8.57699805068226 2013 8.57699805068226 2014 9.94152046783626 2015 9.94152046783626 2016 9.94152046783626 2017 10.7212475633528 2018 15.009746588694 2019 15.009746588694 2020 14.6198830409357 2021 15.2046783625731 2022 17.7387914230019 2023 17.5438596491228