| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 4.74 | 86 |
| 2015 | 4.56 | 107 |
| 2014 | 4.07 | 114 |
| 2013 | 3.82 | 120 |
| 2012 | 3.67 | 120 |
| 2011 | 3.96 | 117 |
| 2010 | 3.87 | 120 |
| 2009 | 4.69 | 113 |
| 2008 | 4.4 | 117 |
| 2007 | 4.41 | 116 |
| 2006 | 4.52 | 117 |
| 2005 | 4.97 | 113 |
| 2004 | 5.62 | 113 |
| 2003 | 6.26 | 112 |
| 2002 | 6.3 | 110 |
| 2001 | 6.59 | 108 |
| 2000 | 6.43 | 107 |
| 1999 | 7.31 | 99 |
| 1998 | 5.62 | 115 |
| 1997 | 6.44 | 110 |
| 1996 | 7.17 | 105 |
| 1995 | 7.16 | 111 |
| 1994 | 6.63 | 105 |
| 1993 | 8.31 | 95 |
| 1992 | 7.39 | 99 |
| 1991 | 14.29 | 73 |
| 1990 | 16.61 | 71 |
| 1989 | 16.81 | 59 |