| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 31.3 | 58 |
| 2014 | 46.6 | 49 |
| 2013 | 55.6 | 39 |
| 2012 | 70.7 | 41 |
| 2011 | 88.4 | 37 |
| 2010 | 60.3 | 45 |
| 2009 | 85.5 | 32 |
| 2008 | 82 | 43 |
| 2007 | 60.3 | 49 |
| 2006 | 48.5 | 48 |
| 2005 | 49.8 | 42 |
| 2004 | 18.7 | 49 |
| 2003 | 20.1 | 43 |
| 2002 | 18.7 | 41 |
| 2001 | 11.9 | 44 |
| 2000 | 11.4 | 43 |
| 1999 | 10 | 50 |
| 1998 | 10.5 | 49 |
| 1997 | 15.4 | 42 |
| 1996 | 15.9 | 35 |
| 1995 | 10.8 | 37 |
| 1994 | 19.6 | 25 |
| 1993 | 13.5 | 24 |
| 1992 | 9 | 28 |
| 1991 | 7.1 | 31 |
| 1990 | 5.9 | 34 |
| 1989 | 18.8 | 14 |
| 1988 | 3.8 | 30 |
| 1987 | 6.1 | 22 |
| 1986 | 1.9 | 31 |