Year current US$ 2000 167.32845905 2001 161.77257587 2002 170.43701644 2003 189.13728812 2004 177.75382283 2005 186.65654688 2006 229.05937844 2007 281.45221601 2008 256.72532611 2009 248.37954648 2010 239.95132659 2011 253.8063382 2012 232.23158186 2013 248.45936576 2014 240.46264122 2015 226.56690204 2016 217.03296829 2017 231.79182987 2018 223.25315284 2019 210.57055215 2020 204.82429317 2021 217.61743814