| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 6 | 109 |
| 2014 | -6.8 | 192 |
| 2013 | 5.2 | 109 |
| 2012 | 5.8 | 115 |
| 2011 | 2.8 | 136 |
| 2010 | 3.1 | 123 |
| 2009 | 3.7 | 113 |
| 2008 | 4.7 | 123 |
| 2007 | -3.2 | 193 |
| 2006 | -2.8 | 193 |
| 2005 | -1 | 189 |
| 2004 | 4.7 | 86 |
| 2003 | 7.1 | 67 |
| 2002 | 9.2 | 56 |
| 2001 | 4.6 | 70 |
| 2000 | 1.2 | 107 |
| 1999 | 0.2 | 141 |
| 1998 | 0.2 | 141 |
| 1997 | 0.4 | 129 |
| 1996 | 0.4 | 114 |
| 1995 | 0.3 | 113 |
| 1994 | 0.3 | 108 |
| 1993 | 0.2 | 118 |
| 1992 | 0 | 136 |
| 1991 | 0 | 117 |
| 1990 | 0.1 | 104 |
| 1989 | 0.2 | 77 |
| 1988 | 0 | 113 |
| 1987 | 0.1 | 92 |
| 1986 | 0.3 | 57 |