Year % 2001 16.54085162723157 2002 16.294942381801395 2003 16.17312546324748 2004 18.7469931315391 2005 18.8591032585842 2006 18.46072861578502 2007 18.285459275077503 2008 17.192778101339545 2009 21.370620758364836 2010 20.629688403675836 2011 20.432960305806866 2012 20.500483477254356 2013 21.041597644551196 2014 20.34376259705592 2015 21.155570458371205 2016 21.05428828725155 2017 20.743754863794038 2018 19.564268478809467 2019 20.192352948837737 2020 21.69203199776586 2021 24.046845331174534 2022 24.280371786523073 2023 21.991945656937403