| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 6 | 148 |
| 2015 | 5.7 | 177 |
| 2014 | 5.9 | 181 |
| 2013 | 5.6 | 185 |
| 2012 | 5.8 | 185 |
| 2011 | 5.8 | 188 |
| 2010 | 5.8 | 186 |
| 2009 | 6.1 | 186 |
| 2008 | 5.9 | 185 |
| 2007 | 5.1 | 186 |
| 2006 | 4.4 | 185 |
| 2005 | 4.4 | 183 |
| 2004 | 4.2 | 183 |
| 2003 | 3.9 | 181 |
| 2002 | 3.7 | 181 |
| 2001 | 3.9 | 175 |
| 2000 | 3.7 | 175 |
| 1999 | 2.9 | 174 |
| 1998 | 2.8 | 174 |
| 1997 | 2.8 | 174 |
| 1996 | 2.6 | 176 |
| 1995 | 2.6 | 174 |
| 1994 | 2.5 | 167 |
| 1993 | 2.3 | 162 |
| 1992 | 2.2 | 160 |
| 1991 | 2.1 | 159 |
| 1990 | 2.1 | 154 |
| 1989 | 2 | 136 |
| 1988 | 1.6 | 133 |
| 1987 | 1.4 | 134 |
| 1986 | 1.2 | 136 |