Year US Dollars adjusted for inflation) 1992 165000000 1993 82000000 1994 236000000 1995 167000000 1996 234000000 1997 558000000 1998 708000000 1999 732000000 2000 270000000 2001 512000000 2002 310000000 2003 313000000 2004 196000000 2005 288000000 2006 524000000 2007 635000000 2008 399000000 2009 442000000 2010 513000000 2011 566000000 2012 1491000000 2013 683000000 2014 630000000 2015 299000000 2016 455000000 2017 375000000 2018 254000000 2019 165000000 2020 116000000 2021 147000000 2022 50000000