| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 9.7 | 63 |
| 2015 | 9.7 | 71 |
| 2014 | 10.3 | 70 |
| 2013 | 10.5 | 70 |
| 2012 | 9.2 | 73 |
| 2011 | 8.2 | 74 |
| 2010 | 7.6 | 76 |
| 2009 | 5.8 | 81 |
| 2008 | 5.7 | 84 |
| 2007 | 4.2 | 85 |
| 2006 | 3.9 | 81 |
| 2005 | 3.5 | 80 |
| 2004 | 2.8 | 82 |
| 2003 | 2.7 | 80 |
| 2002 | 3.4 | 74 |
| 2001 | 5.2 | 65 |
| 2000 | 5.6 | 64 |
| 1999 | 5.7 | 64 |
| 1998 | 5.7 | 62 |
| 1997 | 5.8 | 63 |
| 1996 | 5.8 | 61 |
| 1995 | 5.2 | 60 |
| 1994 | 4.5 | 58 |
| 1993 | 4.2 | 59 |
| 1992 | 3.7 | 58 |
| 1991 | 2.7 | 64 |
| 1990 | 3.3 | 63 |
| 1989 | 3 | 59 |
| 1988 | 2.6 | 59 |
| 1987 | 2.2 | 61 |
| 1986 | 2.4 | 54 |