| 时间 | 值 （亿元） | 世界排名 |
|---|---|---|
| 2015 | 7.3 | 148 |
| 2014 | 6.8 | 150 |
| 2013 | 7.3 | 152 |
| 2012 | 6.1 | 153 |
| 2011 | 6.2 | 154 |
| 2010 | 4.5 | 156 |
| 2009 | 3.7 | 157 |
| 2008 | 2.8 | 163 |
| 2007 | 2 | 163 |
| 2006 | 1.5 | 163 |
| 2005 | 1.1 | 163 |
| 2004 | 0.9 | 163 |
| 2003 | 0.5 | 163 |
| 2002 | 0.5 | 162 |
| 2001 | 0.6 | 161 |
| 2000 | 0.6 | 161 |
| 1999 | 0.5 | 158 |
| 1998 | 0.5 | 158 |
| 1997 | 0.2 | 156 |
| 1996 | 1.6 | 151 |
| 1995 | 0.2 | 154 |
| 1994 | 0.2 | 147 |
| 1993 | 0.2 | 146 |
| 1992 | 0.1 | 136 |
| 1991 | 0.1 | 135 |
| 1989 | 0.1 | 125 |
| 1988 | 0.1 | 122 |
| 1987 | 0.1 | 122 |
| 1986 | 0 | 119 |