| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 74.9 | 9 |
| 2015 | 84.2 | 9 |
| 2014 | 73 | 11 |
| 2013 | 67.8 | 11 |
| 2012 | 84.1 | 9 |
| 2011 | 132.8 | 7 |
| 2010 | 104.5 | 9 |
| 2009 | 138.3 | 5 |
| 2008 | 377.2 | 2 |
| 2007 | 154.6 | 5 |
| 2006 | 119.1 | 6 |
| 2005 | 107.1 | 6 |
| 2004 | 98.9 | 11 |
| 2003 | 94.3 | 7 |
| 2002 | 127.1 | 5 |
| 2001 | 121.4 | 7 |
| 2000 | 143.8 | 6 |
| 1999 | 91.4 | 4 |
| 1998 | 134.2 | 7 |
| 1997 | 119.8 | 3 |
| 1996 | 22.5 | 30 |
| 1995 | 100.5 | 3 |
| 1994 | 120.9 | 3 |
| 1993 | 119.9 | 2 |
| 1992 | 130.8 | 1 |
| 1991 | 118.1 | 1 |
| 1990 | 152.7 | 3 |
| 1989 | 95.3 | 3 |
| 1988 | 137.7 | 3 |
| 1987 | 194.3 | 2 |
| 1986 | 58.9 | 6 |