Year	U.S. dollars (Billions)
1992	0.188
1993	0.116
1994	0.160
1995	0.050
1996	0.018
1997	0.040
1998	-0.167
1999	-0.205
2000	-0.115
2001	-0.144
2003	-0.016
2004	-0.007
2005	0.004
2006	-0.043
2007	-0.081
2008	-0.071
2009	-0.147
2010	-0.182
2011	0.264
2012	0.281
2013	0.045
2014	0.461
2015	0.452
2016	0.297
2017	0.471
2018	0.311
2019	0.257