| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 39 | 75 |
| 2015 | 39.6 | 87 |
| 2014 | 39.8 | 85 |
| 2013 | 43.3 | 86 |
| 2012 | 47.1 | 85 |
| 2011 | 48.3 | 82 |
| 2010 | 47.3 | 84 |
| 2009 | 46.7 | 83 |
| 2008 | 43.9 | 81 |
| 2007 | 41.6 | 81 |
| 2006 | 40.2 | 80 |
| 2005 | 37.6 | 80 |
| 2004 | 36.6 | 79 |
| 2003 | 36.1 | 78 |
| 2002 | 32 | 79 |
| 2001 | 30.9 | 79 |
| 2000 | 30.4 | 76 |
| 1999 | 31.4 | 72 |
| 1998 | 30.2 | 74 |
| 1997 | 26.2 | 75 |
| 1996 | 23.5 | 75 |
| 1995 | 21.8 | 75 |
| 1994 | 24.2 | 70 |
| 1993 | 23.1 | 69 |
| 1992 | 27 | 62 |
| 1991 | 23.7 | 63 |
| 1990 | 23.1 | 62 |
| 1989 | 19.7 | 54 |
| 1988 | 19.1 | 56 |
| 1987 | 17.6 | 57 |
| 1986 | 13.7 | 63 |