Year current US$ 2000 13.94289014 2001 23.90716577 2002 30.85931309 2003 40.67306938 2004 46.84293229 2005 50.72355379 2006 60.72194101 2007 76.21551624 2008 92.34157035 2009 104.27446247 2010 135.76652937 2011 163.56296687 2012 199.89436758 2013 237.12418049 2014 267.56746493 2015 269.08384303 2016 273.64930441 2017 290.11476591 2018 314.63718608 2019 303.63790325 2020 286.57512762 2021 314.88390912