Year	constant 2015 US$
1998	6654521907.425541
1999	6532294728.999732
2000	6879956494.765004
2001	7283337650.627668
2002	7712852233.578558
2003	7650814822.2107525
2004	8653242499.093271
2005	9735163561.173914
2006	10315829211.024353
2007	10882316765.265884
2008	11228339472.45554
2009	12077935211.144129
2010	12764977435.060843
2011	14406990377.92061
2012	17106419501.436268
2013	18958842407.668953
2014	20194348514.740955
2015	19392977893.36801
2016	17509733040.159443
2017	17660019897.894558
2018	18123304821.818867
2019	18573209675.73814
2020	15968290676.703043
2021	16105788576.811563