| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 41.6 | 154 |
| 2014 | 47 | 154 |
| 2013 | 48.6 | 155 |
| 2012 | 52.9 | 150 |
| 2011 | 54.3 | 152 |
| 2010 | 50.2 | 150 |
| 2009 | 41 | 153 |
| 2008 | 37.5 | 154 |
| 2007 | 38.3 | 151 |
| 2006 | 36.3 | 149 |
| 2005 | 35.6 | 144 |
| 2004 | 29.6 | 148 |
| 2003 | 22.3 | 147 |
| 2002 | 15.6 | 154 |
| 2001 | 17.2 | 146 |
| 2000 | 19.8 | 139 |
| 1999 | 18 | 142 |
| 1998 | 18.5 | 142 |
| 1997 | 19.7 | 143 |
| 1996 | 19.4 | 144 |
| 1995 | 19.3 | 140 |
| 1994 | 15.5 | 137 |
| 1993 | 16.2 | 134 |
| 1992 | 15.3 | 134 |
| 1991 | 12.9 | 137 |
| 1990 | 12.2 | 133 |
| 1989 | 7.2 | 119 |
| 1988 | 7.2 | 115 |
| 1987 | 5.9 | 117 |
| 1986 | 5 | 119 |