Year current US$ 1995 30411000000 1996 31884000000 1997 31415000000 1998 31339000000 1999 29570000000 2000 28712000000 2001 26924000000 2002 28213000000 2003 32623000000 2004 37893000000 2005 38364000000 2006 41666000000 2007 46134000000 2015 41415000000 2016 42423000000 2017 46719000000 2018 51602000000 2019 51910000000 2020 20459000000