| 时间 |
值 （亿美元） |
世界排名 |
| 2015 |
1 |
123 |
| 2014 |
1 |
125 |
| 2012 |
0.8 |
127 |
| 2011 |
0.7 |
125 |
| 2010 |
0.5 |
130 |
| 2009 |
0.5 |
131 |
| 2008 |
0.5 |
133 |
| 2004 |
0.5 |
128 |
| 2003 |
0.3 |
130 |
| 2002 |
0.3 |
129 |
| 2001 |
0.1 |
136 |
| 2000 |
0.1 |
135 |
| 1999 |
0.2 |
132 |
| 1998 |
0.2 |
125 |
| 1997 |
0.2 |
130 |
| 1996 |
0.1 |
132 |
| 1995 |
0.1 |
129 |
| 1994 |
0.3 |
117 |
| 1993 |
0.6 |
100 |
| 1992 |
0.1 |
120 |