| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.74 | 70 |
| 2015 | 6.06 | 75 |
| 2014 | 6.07 | 75 |
| 2013 | 5.66 | 67 |
| 2012 | 5.22 | 57 |
| 2011 | 5.08 | 55 |
| 2010 | 5.21 | 52 |
| 2009 | 5.56 | 58 |
| 2008 | 4.23 | 49 |
| 2007 | 4.38 | 48 |
| 2006 | 4.78 | 54 |
| 2005 | 5.03 | 53 |
| 2004 | 5.39 | 57 |
| 2003 | 5.93 | 60 |
| 2002 | 6.37 | 68 |
| 2001 | 6.74 | 74 |
| 2000 | 6.28 | 67 |
| 1999 | 6.87 | 77 |
| 1998 | 7.68 | 89 |
| 1997 | 8.36 | 96 |
| 1996 | 8.51 | 98 |
| 1995 | 8.47 | 100 |
| 1994 | 9.72 | 117 |
| 1993 | 10.87 | 123 |
| 1992 | 10.73 | 125 |
| 1991 | 9.58 | 116 |