| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 16.17 | 160 |
| 2015 | 15.74 | 169 |
| 2014 | 18.58 | 169 |
| 2013 | 18.51 | 173 |
| 2012 | 17.52 | 173 |
| 2011 | 18.65 | 176 |
| 2010 | 16.64 | 176 |
| 2009 | 17.12 | 176 |
| 2008 | 17.89 | 175 |
| 2007 | 15.14 | 176 |
| 2006 | 11.08 | 181 |
| 2005 | 9.72 | 178 |
| 2004 | 9.24 | 176 |
| 2003 | 8.14 | 177 |
| 2002 | 6.21 | 180 |
| 2001 | 5.63 | 180 |
| 2000 | 5.39 | 181 |
| 1999 | 5.92 | 177 |
| 1998 | 5.22 | 176 |
| 1997 | 4.91 | 176 |
| 1996 | 5.02 | 175 |
| 1995 | 4.87 | 175 |
| 1994 | 4.07 | 167 |
| 1993 | 4.9 | 159 |
| 1992 | 3.57 | 163 |
| 1991 | 3.2 | 163 |
| 1990 | 3.07 | 162 |
| 1989 | 2.67 | 150 |
| 1988 | 2.64 | 149 |
| 1987 | 2.35 | 146 |
| 1986 | 1.91 | 142 |