| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 68.8 | 38 |
| 2014 | 47.8 | 47 |
| 2013 | 41.9 | 43 |
| 2012 | 28 | 66 |
| 2011 | -4.8 | 189 |
| 2010 | 63.9 | 44 |
| 2009 | 67.1 | 37 |
| 2008 | 94.9 | 39 |
| 2007 | 115.8 | 37 |
| 2006 | 100.4 | 34 |
| 2005 | 53.8 | 40 |
| 2004 | 12.5 | 58 |
| 2003 | 2.4 | 95 |
| 2002 | 6.5 | 67 |
| 2001 | 5.1 | 67 |
| 2000 | 12.4 | 42 |
| 1999 | 10.7 | 47 |
| 1998 | 10.8 | 48 |
| 1997 | 8.9 | 51 |
| 1996 | 6.4 | 48 |
| 1995 | 6 | 46 |
| 1994 | 12.6 | 33 |
| 1993 | 4.9 | 45 |
| 1992 | 4.6 | 39 |
| 1991 | 2.5 | 44 |
| 1990 | 7.3 | 29 |
| 1989 | 12.5 | 22 |
| 1988 | 11.9 | 15 |
| 1987 | 9.5 | 17 |
| 1986 | 12.2 | 13 |