| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 4.5 | 55 |
| 2015 | 18.9 | 69 |
| 2014 | 51 | 42 |
| 2013 | -8.6 | 189 |
| 2012 | 27.5 | 67 |
| 2011 | 135.6 | 30 |
| 2010 | -117.7 | 194 |
| 2009 | 39.2 | 49 |
| 2008 | 21.9 | 73 |
| 2007 | 118.1 | 36 |
| 2006 | 24.2 | 65 |
| 2005 | 128.3 | 22 |
| 2004 | -88 | 192 |
| 2003 | 11.8 | 56 |
| 2002 | 44.3 | 24 |
| 2001 | 92.9 | 18 |
| 2000 | 360.1 | 10 |
| 1999 | 168.5 | 14 |
| 1998 | 66.7 | 19 |
| 1997 | 27.9 | 33 |
| 1996 | 7.7 | 46 |
| 1995 | 41.4 | 20 |
| 1994 | 50.1 | 12 |
| 1993 | 17.1 | 20 |
| 1992 | 10.2 | 26 |
| 1991 | 15.5 | 20 |
| 1990 | 11.3 | 22 |
| 1989 | 10.9 | 25 |
| 1988 | 5 | 27 |
| 1987 | 0.8 | 48 |
| 1986 | 1.6 | 33 |