Year % 1997 11.48243359040274 1998 10.968294772922032 1999 11.482433590402747 2000 12.960082944530845 2001 15.566835871404386 2002 16.116751269035518 2003 16.26751016719384 2004 17.141641854529983 2005 16.723404255319164 2006 17.099106763079543 2007 16.843896214376873 2008 16.81528662420381 2009 17.07006369426751 2010 17.027600849256892 2011 18.433375904640258 2012 19.267188143268832 2013 19.210201563142732 2014 19.705093833780158 2015 20.116487455197138 2016 19.89247311827957 2017 22.304488662656183 2018 22.72096251735308 2019 23.692734844979178 2020 24.98843128181398 2021 24.212962962962973 2022 25.06938020351527 2023 25.531914893617028