| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 63.4 | 63 |
| 2015 | 62.3 | 73 |
| 2014 | 64.7 | 74 |
| 2013 | 65 | 76 |
| 2012 | 55.2 | 79 |
| 2011 | 48.7 | 81 |
| 2010 | 46.2 | 86 |
| 2009 | 51.1 | 77 |
| 2008 | 45.3 | 80 |
| 2007 | 47 | 76 |
| 2006 | 44.4 | 75 |
| 2005 | 41.8 | 76 |
| 2004 | 35.5 | 80 |
| 2003 | 30.9 | 81 |
| 2002 | 24 | 85 |
| 2001 | 20.3 | 88 |
| 2000 | 19.1 | 89 |
| 1999 | 18.7 | 86 |
| 1998 | 19 | 84 |
| 1997 | 19.3 | 84 |
| 1996 | 20.2 | 80 |
| 1995 | 30.2 | 70 |
| 1994 | 32.8 | 63 |
| 1993 | 35.6 | 63 |
| 1992 | 40 | 59 |
| 1991 | 40.6 | 58 |
| 1990 | 35.3 | 59 |