| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 37.8 | 132 |
| 2015 | 38.3 | 155 |
| 2014 | 38.9 | 156 |
| 2013 | 34.4 | 161 |
| 2012 | 31.8 | 162 |
| 2011 | 30.2 | 163 |
| 2010 | 26.4 | 163 |
| 2009 | 23.7 | 164 |
| 2008 | 20.7 | 166 |
| 2007 | 17.2 | 166 |
| 2006 | 17.8 | 162 |
| 2005 | 14 | 163 |
| 2004 | 10.8 | 167 |
| 2003 | 9 | 168 |
| 2002 | 9.3 | 164 |
| 2001 | 9.7 | 160 |
| 2000 | 9.6 | 157 |
| 1999 | 8.8 | 157 |
| 1998 | 10 | 156 |
| 1997 | 10.2 | 154 |
| 1996 | 9.6 | 156 |
| 1995 | 11.4 | 152 |
| 1994 | 10.9 | 143 |
| 1993 | 11.1 | 140 |
| 1992 | 13.1 | 137 |
| 1991 | 13.8 | 135 |
| 1990 | 13.6 | 131 |
| 1989 | 12.6 | 114 |
| 1988 | 12.3 | 110 |
| 1987 | 13.1 | 110 |
| 1986 | 13.3 | 107 |