Year US Dollars 2003 13.29485 2004 32.8196 2005 6.28397 2006 155.42457 2007 171.54455 2008 169.3278 2009 123.71137 2010 129.26442 2011 204.21591 2012 166.11317 2013 188.63278 2014 161.49627 2015 160.66632 2016 137.76248 2017 189.58084 2018 251.06593 2019 154.10882 2020 329.96622 2021 213.013