Year current US$ 2000 2161.85302734 2001 2192.71557617 2002 2449.75830078 2003 3006.3059082 2004 3458.62744141 2005 3575.02514648 2006 3811.55175781 2007 4312.31054688 2008 4807.37451172 2009 4737.578125 2010 4592.38330078 2011 4931.87792969 2012 4644.59570313 2013 4884.76660156 2014 4980.81494141 2015 4201.78173828 2016 4256.765625 2017 4410.59912109 2018 4666.97998047 2019 4504.48486328 2020 4755.44042969 2021 5380.875