| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 7.69 | 105 |
| 2015 | 7.56 | 104 |
| 2014 | 8.05 | 107 |
| 2013 | 8.33 | 108 |
| 2012 | 8.43 | 110 |
| 2011 | 8.53 | 112 |
| 2010 | 8.64 | 112 |
| 2009 | 8.41 | 108 |
| 2008 | 8.2 | 123 |
| 2007 | 8.2 | 112 |
| 2006 | 8.27 | 111 |
| 2005 | 8.11 | 104 |
| 2004 | 8.53 | 105 |
| 2003 | 9.9 | 117 |
| 2002 | 12.55 | 137 |
| 2001 | 7.8 | 96 |
| 2000 | 7.5 | 89 |
| 1999 | 7.83 | 93 |
| 1998 | 9.71 | 113 |
| 1997 | 8.27 | 95 |
| 1996 | 8.6 | 100 |
| 1995 | 8.56 | 101 |
| 1994 | 8.51 | 101 |
| 1993 | 8.45 | 101 |
| 1992 | 8.4 | 102 |
| 1991 | 8.37 | 103 |