Year current US$ 2000 77.74626923 2001 76.11361694 2002 75.27822876 2003 132.39044189 2004 177.11592102 2005 218.70697021 2006 238.984375 2007 253.80125427 2008 267.72537231 2009 282.30490112 2010 346.70117188 2011 369.37054443 2012 343.8296814 2013 306.57077026 2014 285.05142212 2015 252.67782593 2016 227.801651 2017 267.07046509 2018 266.45422363 2019 274.94509888 2020 222.53158569 2021 279.91430664