| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 11 | 125 |
| 2014 | 11 | 124 |
| 2013 | 9.9 | 130 |
| 2012 | 10.1 | 128 |
| 2011 | 9.2 | 128 |
| 2010 | 9 | 140 |
| 2009 | 8.6 | 131 |
| 2008 | 8 | 131 |
| 2007 | 7.3 | 129 |
| 2006 | 6.3 | 130 |
| 2005 | 5.8 | 128 |
| 2004 | 5.2 | 127 |
| 2003 | 5 | 127 |
| 2002 | 4.7 | 126 |
| 2001 | 3.8 | 128 |
| 2000 | 3.5 | 126 |
| 1999 | 3.2 | 121 |
| 1998 | 3.2 | 120 |
| 1997 | 2.4 | 121 |
| 1996 | 2 | 121 |
| 1995 | 1.9 | 118 |
| 1994 | 1.6 | 113 |
| 1993 | 1.4 | 111 |
| 1992 | 1.2 | 106 |
| 1991 | 0.9 | 105 |
| 1990 | 0.7 | 105 |
| 1989 | 0.6 | 92 |
| 1988 | 0.6 | 91 |
| 1987 | 0.4 | 91 |
| 1986 | 0.2 | 90 |