Year % 2000 28.138 2001 29.334 2002 30.776 2003 28.537 2004 23.024 2005 21.504 2006 20.956 2007 20.997 2008 25.193 2009 23.252 2010 25.422 2011 26.074 2012 27.132 2013 26.329 2014 27.848 2015 27.876 2016 29.517 2017 29.191 2018 28.858 2019 32.009 2020 31.467 2021 34.309 2022 31.527 2023 33.793