| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 6.05 | 78 |
| 2015 | 6.17 | 76 |
| 2014 | 6.59 | 85 |
| 2013 | 7 | 89 |
| 2012 | 7.53 | 99 |
| 2011 | 7.57 | 99 |
| 2010 | 7.46 | 92 |
| 2009 | 6.01 | 65 |
| 2008 | 3.43 | 36 |
| 2007 | 3.8 | 40 |
| 2006 | 3.9 | 39 |
| 2005 | 4.83 | 49 |
| 2004 | 5.2 | 54 |
| 2003 | 5.4 | 52 |
| 2002 | 4.27 | 40 |
| 2001 | 4.16 | 42 |
| 2000 | 4.48 | 43 |
| 1999 | 5.14 | 49 |
| 1998 | 5.04 | 49 |
| 1997 | 5.4 | 55 |
| 1996 | 6.84 | 76 |
| 1995 | 6.99 | 80 |
| 1994 | 8.04 | 93 |
| 1993 | 10.72 | 122 |
| 1992 | 9.03 | 110 |
| 1991 | 9.1 | 112 |