Year current US$ 2000 144.1492294816292 2001 150.74305785532638 2002 149.39183645488953 2003 145.88524516585946 2004 160.7834358891387 2005 179.82966406267346 2006 201.07035561123288 2007 235.04777121265616 2008 279.44841318364007 2009 304.4579305458693 2010 331.07340062351886 2011 379.0139571220246 2012 399.7359172339252 2013 418.3751926623759 2014 439.30008533899087 2015 421.9023951957055 2016 465.4873519045353 2017 471.88905817618166 2018 495.40313014229423 2019 484.290415381236 2020 489.61135794587847 2021 537.0598462309326