Year % 1998 15.099629518373897 1999 14.768813276275978 2000 14.344957587181904 2001 14.20102152499088 2002 15.90204897551224 2003 15.50429669832656 2004 16.38893813153697 2005 15.747569560844779 2006 16.69315045579994 2007 17.529913128995236 2008 18.034548309777666 2009 19.065862406260187 2010 19.032546059573086 2011 19.76401179941002 2012 21.570404548076127 2013 22.48768472906405 2014 22.872115628433782 2015 23.246630612069715 2016 23.990259467629535 2017 24.173588743854882 2018 25.345001682935038 2019 25.985342019543967 2020 26.323074417847256 2021 26.439511835531157 2022 26.737880032867697 2023 27.16172439571393