| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 2.21 | 36 |
| 2015 | 2.14 | 44 |
| 2014 | 2.01 | 46 |
| 2013 | 2.24 | 40 |
| 2012 | 2.39 | 35 |
| 2008 | 2.72 | 34 |
| 2007 | 3.41 | 17 |
| 2006 | 3.51 | 17 |
| 2005 | 4.44 | 10 |
| 2004 | 4.9 | 10 |
| 2003 | 5.53 | 10 |
| 2002 | 5.44 | 10 |
| 2001 | 6.07 | 7 |
| 2000 | 4.86 | 16 |
| 1999 | 6.26 | 9 |
| 1998 | 6.57 | 7 |
| 1997 | 6.36 | 8 |
| 1996 | 5.86 | 11 |
| 1995 | 4.21 | 19 |
| 1994 | 4.53 | 18 |
| 1993 | 3.86 | 29 |
| 1992 | 3.6 | 31 |
| 1991 | 3.66 | 34 |
| 1990 | 3.5 | 41 |
| 1989 | 3.4 | 41 |
| 1988 | 3.16 | 41 |
| 1987 | 2.72 | 54 |
| 1986 | 2.88 | 43 |