Year % 2001 28.179696616102685 2002 26.524306726068374 2003 28.054498144186457 2004 27.459112094873433 2005 23.694985617641215 2006 21.150819672131146 2007 18.237494038804247 2008 15.880852123047564 2009 14.394328182319288 2010 14.567929759704251 2011 13.478170333865483 2012 13.411642068062493 2013 13.893471890467628 2014 13.613306594314025 2015 18.083608438938388 2016 18.051082483449633 2017 17.367245574852493 2018 17.82857919659243 2019 15.215534726818541 2020 19.68037238169123 2021 18.429907581642397 2022 20.317539961293097 2023 20.184690981488544