Year current US$ 2000 328.68823576 2001 376.97230081 2002 419.63909399 2003 832.53123724 2004 940.45511462 2005 1009.78779949 2006 989.01079904 2007 954.60321652 2008 953.78111887 2009 927.08237126 2010 927.50652136 2011 1094.22844222 2012 1356.48537986 2013 1706.14404047 2014 1957.27367395 2015 2140.18200854 2016 1780.85640953 2017 1611.44198149 2018 1661.64479719 2019 1710.25087741 2020 1731.61570099 2021 1644.47907872