| 时间 |
值 （亿美元） |
世界排名 |
| 2012 |
1.1 |
83 |
| 2011 |
0.6 |
89 |
| 2010 |
1.9 |
76 |
| 2009 |
0.5 |
89 |
| 2008 |
2.6 |
80 |
| 2007 |
1.2 |
88 |
| 2006 |
1.4 |
86 |
| 2005 |
0.7 |
86 |
| 2004 |
0.5 |
90 |
| 2003 |
0.4 |
84 |
| 2002 |
0.6 |
80 |
| 2001 |
0.5 |
84 |
| 2000 |
1.5 |
72 |
| 1999 |
0.5 |
80 |
| 1998 |
1.2 |
71 |
| 1997 |
0.6 |
77 |
| 1996 |
0.2 |
74 |
| 1995 |
0.1 |
77 |
| 1994 |
0.7 |
65 |
| 1993 |
0.1 |
64 |
| 1992 |
0 |
63 |