| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.15 | 52 |
| 2015 | 3.19 | 53 |
| 2014 | 3.23 | 52 |
| 2013 | 3.23 | 55 |
| 2012 | 3.2 | 59 |
| 2011 | 3.14 | 62 |
| 2010 | 3.08 | 64 |
| 2009 | 3.04 | 63 |
| 2008 | 3.04 | 67 |
| 2007 | 3.11 | 66 |
| 2006 | 3.23 | 63 |
| 2005 | 3.38 | 60 |
| 2004 | 3.51 | 54 |
| 2003 | 3.64 | 51 |
| 2002 | 3.76 | 49 |
| 2001 | 5.67 | 10 |
| 2000 | 5.99 | 7 |
| 1999 | 6.11 | 7 |
| 1998 | 6.24 | 7 |
| 1997 | 6.4 | 5 |
| 1996 | 6.58 | 4 |
| 1995 | 6.75 | 3 |
| 1994 | 6.93 | 5 |
| 1993 | 7.02 | 5 |
| 1992 | 7.03 | 7 |
| 1991 | 6.23 | 11 |
| 1990 | 6.06 | 14 |
| 1989 | 5.93 | 18 |
| 1988 | 5.86 | 20 |
| 1987 | 5.84 | 23 |
| 1986 | 5.87 | 28 |