Year % 2001 15.052855391421394 2002 16.66600868962172 2003 17.386714241746887 2004 17.18312231119004 2005 15.023007485486477 2006 15.923455499389977 2007 17.091135826219706 2008 16.149944059967893 2009 20.341627619062894 2010 23.412313093267404 2011 21.075868617383037 2012 20.138878882532467 2013 21.064919078129755 2014 22.178426219562787 2015 22.858005817700025 2016 22.224560773681628 2017 20.505706013319596 2018 21.773581351552814 2019 21.673207318746 2020 22.634371003484 2021 22.74409947455522 2022 22.16649782957807 2023 20.778729409550017