Year current international $ 2000 21.2013511778082 2001 22.7700570406343 2002 23.6154912943524 2003 23.9957919247947 2004 24.512234897834 2005 26.531537384412 2006 27.6906506041231 2007 27.5712444188915 2008 27.6468769767419 2009 28.368791922458 2010 28.8853997187222 2011 29.7053098020959 2012 30.012242484407 2013 28.1911351573476 2014 27.5406227460394 2015 31.454087799554 2016 30.2580536604162 2017 31.1421355671745 2018 31.72292855564 2019 33.1412168183624 2020 34.4221433845981 2021 32.2341685018757