| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 9 | 147 |
| 2015 | 8 | 152 |
| 2014 | 8 | 156 |
| 2013 | 8 | 156 |
| 2012 | 10 | 154 |
| 2011 | 12 | 149 |
| 2010 | 9 | 149 |
| 2009 | 7 | 152 |
| 2008 | 9 | 150 |
| 2007 | 8 | 148 |
| 2006 | 7 | 147 |
| 2005 | 7 | 145 |
| 2004 | 7 | 140 |
| 2003 | 5 | 147 |
| 2002 | 4 | 148 |
| 2001 | 3 | 152 |
| 2000 | 2 | 158 |
| 1999 | 2 | 161 |
| 1998 | 2 | 158 |
| 1997 | 2 | 157 |
| 1996 | 2 | 157 |
| 1995 | 2 | 159 |
| 1994 | 1 | 156 |
| 1993 | 1 | 139 |
| 1992 | 1 | 143 |
| 1991 | 1 | 149 |
| 1990 | 1 | 150 |
| 1989 | 1 | 144 |
| 1988 | 1 | 144 |
| 1987 | 0 | 145 |
| 1986 | 0 | 150 |