Year current US$ 1990 3865822.83951752 1991 3851285.39682496 1992 4048284.52842736 1993 4124166.09565258 1994 4194960.32036688 1995 4697583.67328534 1996 5039888.02651589 1997 5111403.08686931 1998 5282172.40235588 1999 5240872.05639038 2000 5373585.98130972 2001 5294874.93519901 2002 5304263.22997322 2003 5120028.06904966 2004 5277033.12337394 2005 5456595.59367159 2006 5648804.65522518 2007 5799025.10129298 2008 5742634.71291233 2009 5501257.49796121 2010 5546559.35083367 2011 5762017.89281432 2012 5679057.13555046 2013 5842366.4548187 2014 5958268.83224745 2015 6226072.17005703 2016 6456989.66878639 2017 6559086.56660243 2018 6593561.97479126 2019 6729691.29668071 2020 6626164.48898415 2021 7026137.19980035