Year current international $ 2000 26.1300172200472 2001 25.5943817255767 2002 25.2345181101392 2003 28.9530121120957 2004 25.3648496107644 2005 28.3215474396414 2006 28.0781765627211 2007 29.8006807153529 2008 29.7660341270128 2009 30.0937235275506 2010 31.192584654079 2011 25.0440698328429 2012 24.8830842268563 2013 25.200691954165 2014 24.2602737841781 2015 24.2000517771442 2016 24.6368173008862 2017 22.5269519777139 2018 23.3348056844779 2019 20.3954296706172 2020 20.2296527519651 2021 21.8260809973303