| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 15.2 | 139 |
| 2015 | 14.2 | 166 |
| 2014 | 14.3 | 169 |
| 2013 | 13.7 | 173 |
| 2012 | 13.7 | 172 |
| 2011 | 12.5 | 175 |
| 2010 | 13 | 174 |
| 2009 | 13.6 | 173 |
| 2008 | 16.9 | 168 |
| 2007 | 16.5 | 167 |
| 2006 | 14.2 | 166 |
| 2005 | 11.5 | 167 |
| 2004 | 9.7 | 168 |
| 2003 | 9.2 | 167 |
| 2002 | 8.6 | 165 |
| 2001 | 8.4 | 161 |
| 2000 | 8.6 | 160 |
| 1999 | 8.2 | 162 |
| 1998 | 7.5 | 161 |
| 1997 | 7.2 | 163 |
| 1996 | 7 | 162 |
| 1995 | 6.1 | 163 |
| 1994 | 5.7 | 157 |
| 1993 | 4.9 | 152 |
| 1992 | 4.8 | 149 |
| 1991 | 4.7 | 147 |
| 1990 | 4.5 | 142 |
| 1989 | 4.9 | 121 |
| 1988 | 4.2 | 118 |
| 1987 | 4.1 | 118 |
| 1986 | 3.8 | 120 |