| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 30.45 | 45 |
| 2015 | 30.49 | 54 |
| 2014 | 30.53 | 56 |
| 2013 | 30.18 | 60 |
| 2012 | 30.71 | 60 |
| 2011 | 30.57 | 61 |
| 2010 | 30.16 | 59 |
| 2009 | 27.81 | 76 |
| 2008 | 30.06 | 66 |
| 2007 | 30.53 | 69 |
| 2006 | 30.12 | 70 |
| 2005 | 29.4 | 72 |
| 2004 | 29.42 | 74 |
| 2003 | 29.25 | 72 |
| 2002 | 29.36 | 74 |
| 2001 | 30.11 | 68 |
| 2000 | 30.91 | 64 |
| 1999 | 30.81 | 58 |
| 1998 | 31.37 | 52 |
| 1997 | 31.52 | 54 |
| 1996 | 31.86 | 53 |
| 1995 | 32.91 | 49 |
| 1994 | 33.54 | 42 |
| 1993 | 33.82 | 43 |
| 1992 | 35.92 | 38 |
| 1991 | 36.9 | 35 |