Year current international $ 2000 33.1316448775459 2001 29.2826286296947 2002 31.6155351549777 2003 27.4012287417379 2004 15.9395830807588 2005 17.0530301868721 2006 18.7471180156939 2007 19.7389704891098 2008 21.0792725448381 2009 21.7501088284772 2010 21.9249824144077 2011 21.8158976030072 2012 21.2800206772044 2013 20.1763641659238 2014 20.7213379231306 2015 20.4301483585347 2016 20.1759191547921 2017 20.4835716767192 2018 20.352565008672 2019 21.747367419181 2020 21.9063051285498 2021 23.27464930253