| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 60.2 | 27 |
| 2015 | 77.4 | 27 |
| 2014 | 86.6 | 26 |
| 2013 | 78.4 | 28 |
| 2012 | 69.8 | 28 |
| 2011 | 64.7 | 29 |
| 2010 | 59 | 27 |
| 2009 | 48.6 | 31 |
| 2008 | 49.4 | 30 |
| 2007 | 47.8 | 29 |
| 2006 | 40.8 | 29 |
| 2005 | 36.2 | 31 |
| 2004 | 31.3 | 33 |
| 2003 | 32.5 | 30 |
| 2002 | 34.8 | 25 |
| 2001 | 35.4 | 24 |
| 2000 | 33.2 | 23 |
| 1999 | 29.1 | 30 |
| 1998 | 24.8 | 32 |
| 1997 | 23.9 | 36 |
| 1996 | 20.6 | 39 |
| 1995 | 17.1 | 43 |
| 1994 | 28.9 | 29 |
| 1993 | 23.3 | 31 |
| 1992 | 20 | 35 |
| 1991 | 16 | 36 |
| 1990 | 13.3 | 41 |
| 1989 | 11.5 | 41 |
| 1988 | 9.8 | 44 |
| 1987 | 8.1 | 47 |
| 1986 | 8.2 | 41 |