| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 2 | 166 |
| 2014 | 2 | 173 |
| 2013 | 2 | 179 |
| 2012 | 2 | 180 |
| 2011 | 2 | 181 |
| 2010 | 1 | 181 |
| 2009 | 1 | 180 |
| 2008 | 2 | 181 |
| 2007 | 1 | 183 |
| 2006 | 1 | 183 |
| 2005 | 1 | 181 |
| 2004 | 1 | 182 |
| 2003 | 1 | 179 |
| 2002 | 1 | 178 |
| 2001 | 1 | 176 |
| 2000 | 1 | 175 |
| 1999 | 1 | 171 |
| 1998 | 1 | 170 |
| 1997 | 1 | 172 |
| 1996 | 1 | 170 |
| 1995 | 1 | 170 |
| 1994 | 1 | 153 |
| 1993 | 1 | 146 |
| 1992 | 1 | 144 |
| 1991 | 0 | 142 |
| 1990 | 0 | 140 |