Year	U.S. dollars (Billions)
1980	5.176
1981	4.436
1982	-3.878
1983	4.803
1984	5.045
1985	3.717
1986	-1.987
1987	-1.390
1988	-5.539
1989	2.439
1990	8.452
1991	1.924
1992	-3.753
1993	-1.993
1994	2.623
1995	2.136
1996	8.989
1997	3.732
1998	-4.432
1999	2.112
2000	11.853
2001	1.983
2002	7.599
2003	11.796
2004	15.519
2005	25.447
2006	26.462
2007	13.464
2008	31.297
2009	0.429
2010	5.585
2011	16.342
2012	2.586
2013	4.604
2014	4.919
2015	-16.051
2016	-3.870
2017	8.706
2018	8.613
2019	4.296
2020	-1.529
2021	-0.684
2022	3.308
2023	3.312
2024	4.823
2025	4.197