Year % 2001 20.24209 2002 21.05528 2004 18.71347 2005 18.07318 2006 18.09358 2007 17.91892 2008 27.61328 2009 26.97409 2010 18.51237 2011 25.85319 2012 16.42199 2013 18.77437 2014 26.93761 2015 28.44274 2016 29.10993 2017 14.9441 2018 8.708595 2019 18.8013 2020 20.88158 2021 21.1312