| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2016 | 46.8 | 35 |
| 2015 | 45.2 | 39 |
| 2014 | 46.1 | 41 |
| 2013 | 50.3 | 39 |
| 2012 | 45.9 | 38 |
| 2011 | 49.7 | 36 |
| 2010 | 41.2 | 40 |
| 2009 | 40.6 | 36 |
| 2008 | 41 | 40 |
| 2007 | 35.2 | 39 |
| 2006 | 33.3 | 36 |
| 2005 | 34.8 | 34 |
| 2004 | 35 | 31 |
| 2003 | 32.7 | 29 |
| 2002 | 28.8 | 30 |
| 2001 | 27.6 | 32 |
| 2000 | 28 | 30 |
| 1999 | 31.5 | 29 |
| 1998 | 34.9 | 24 |
| 1997 | 35 | 24 |
| 1996 | 42.4 | 23 |
| 1995 | 46.5 | 20 |
| 1994 | 39 | 21 |
| 1993 | 36.1 | 21 |
| 1992 | 41.4 | 21 |
| 1991 | 40.2 | 21 |
| 1990 | 40.6 | 22 |
| 1989 | 30.8 | 22 |
| 1988 | 32.8 | 20 |
| 1987 | 30.2 | 20 |
| 1986 | 25.7 | 22 |