Year % 1997 8.331444116980279 1998 8.843106180665611 1999 8.808977917219742 2000 9.673024523160764 2001 9.521619135234593 2002 11.088550479413426 2003 11.265911596672348 2004 12.145948072383952 2005 12.886882829771555 2006 13.43156701615189 2007 14.721203935944434 2008 15.545093695190616 2009 16.98824374046487 2010 17.42120842765106 2011 17.557797018655716 2012 19.294201099485726 2013 20.069270733115268 2014 21.07317958961323 2015 22.16251273973872 2016 22.34532128856315 2017 22.30537634408603 2018 22.789593953243106 2019 22.948551664504972 2020 24.450912939931207 2021 24.279359430604988 2022 24.86167119947483 2023 25.13650913199021