| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.25 | 60 |
| 2015 | 5.36 | 65 |
| 2014 | 5.38 | 63 |
| 2013 | 5.76 | 69 |
| 2012 | 6.41 | 76 |
| 2011 | 5.97 | 68 |
| 2010 | 6.14 | 63 |
| 2009 | 5.82 | 61 |
| 2008 | 4.02 | 46 |
| 2007 | 3.6 | 33 |
| 2006 | 3.85 | 37 |
| 2005 | 3.81 | 31 |
| 2004 | 4.01 | 35 |
| 2003 | 4.75 | 45 |
| 2002 | 5.28 | 52 |
| 2001 | 5.45 | 58 |
| 2000 | 6.14 | 66 |
| 1999 | 7.04 | 80 |
| 1998 | 7.72 | 92 |
| 1997 | 6.85 | 79 |
| 1996 | 6.3 | 64 |
| 1995 | 6.46 | 69 |
| 1994 | 8.36 | 99 |
| 1993 | 9.8 | 113 |
| 1992 | 10.67 | 124 |
| 1991 | 10.61 | 128 |