| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 12 | 141 |
| 2015 | 11.6 | 168 |
| 2014 | 10.8 | 172 |
| 2013 | 10.5 | 176 |
| 2012 | 9.9 | 178 |
| 2011 | 9.8 | 180 |
| 2010 | 9.7 | 178 |
| 2009 | 9.5 | 177 |
| 2008 | 10.7 | 176 |
| 2007 | 9.9 | 177 |
| 2006 | 9.4 | 172 |
| 2005 | 9.4 | 172 |
| 2004 | 7.2 | 176 |
| 2003 | 7.2 | 171 |
| 2002 | 6.4 | 171 |
| 2001 | 6 | 168 |
| 2000 | 5.9 | 168 |
| 1999 | 5.3 | 167 |
| 1998 | 5.3 | 167 |
| 1997 | 4.7 | 168 |
| 1996 | 4.3 | 167 |
| 1995 | 3.9 | 166 |
| 1994 | 3.6 | 160 |
| 1993 | 3.6 | 155 |
| 1992 | 3.5 | 152 |
| 1991 | 3.5 | 150 |
| 1990 | 3.2 | 147 |
| 1989 | 3.1 | 129 |
| 1988 | 2.7 | 126 |
| 1987 | 2.5 | 126 |
| 1986 | 2.2 | 127 |