| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 59.8 | 30 |
| 2015 | 50.6 | 45 |
| 2014 | 49.8 | 45 |
| 2013 | 42.7 | 42 |
| 2012 | 33.8 | 56 |
| 2011 | 44 | 50 |
| 2010 | 25.5 | 58 |
| 2009 | 10.9 | 85 |
| 2008 | 23.9 | 71 |
| 2007 | 22.2 | 75 |
| 2006 | 29.4 | 59 |
| 2005 | 11 | 74 |
| 2004 | 12.8 | 57 |
| 2003 | 10.5 | 57 |
| 2002 | 2.5 | 87 |
| 2001 | 6.1 | 60 |
| 2000 | 8.3 | 54 |
| 1999 | 7.6 | 55 |
| 1998 | 12 | 44 |
| 1997 | 13 | 44 |
| 1996 | 4.2 | 55 |
| 1995 | 2.2 | 65 |
| 1994 | 4 | 52 |
| 1993 | 1.7 | 63 |
| 1992 | 1.4 | 53 |
| 1991 | 1.1 | 59 |
| 1990 | 1.4 | 52 |
| 1989 | 0.5 | 62 |
| 1988 | -6 | 145 |
| 1987 | -5.6 | 144 |
| 1986 | 0.2 | 64 |