| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 78.2 | 37 |
| 2014 | 78.8 | 35 |
| 2013 | 93 | 33 |
| 2012 | 119.2 | 30 |
| 2011 | 76.6 | 40 |
| 2010 | 84.5 | 38 |
| 2009 | 64.3 | 38 |
| 2008 | 69.2 | 47 |
| 2007 | 54.9 | 52 |
| 2006 | 34.7 | 55 |
| 2005 | 25.8 | 55 |
| 2004 | 16 | 52 |
| 2003 | 13.4 | 55 |
| 2002 | 21.6 | 37 |
| 2001 | 11.4 | 47 |
| 2000 | 8.1 | 55 |
| 1999 | 19.4 | 37 |
| 1998 | 16.4 | 42 |
| 1997 | 21.4 | 39 |
| 1996 | 34.7 | 22 |
| 1995 | 25.6 | 25 |
| 1994 | 32.9 | 17 |
| 1993 | 7.6 | 38 |
| 1992 | -.8 | 167 |
| 1991 | -.1 | 146 |
| 1990 | 0.4 | 78 |
| 1989 | 0.6 | 59 |
| 1988 | 0.3 | 70 |
| 1987 | 0.3 | 69 |
| 1986 | 0.2 | 62 |