Year % 1997 10.109242240332932 1998 10.846650799047946 2000 11.512089498376037 2001 12.224264705882355 2002 13.375042272573554 2003 13.628875243372772 2004 14.669990814853698 2005 16.17931212160248 2006 16.58393788977982 2007 17.279364672729606 2008 17.7757755180847 2009 18.44231254733653 2010 18.71616395978345 2011 20.443622920517562 2012 21.288753799392097 2013 22.37535953978907 2014 22.072794571252313 2015 23.562687601015927 2016 23.819915010910762 2017 24.027280858676217 2018 24.084821428571434 2019 24.08902214022141 2020 24.871013133208262 2021 25.937758845107105 2022 26.35228848821082 2023 27.051206592113008