| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.25 | 46 |
| 2015 | 3.27 | 49 |
| 2014 | 3.29 | 49 |
| 2013 | 3.27 | 51 |
| 2012 | 3.23 | 57 |
| 2011 | 3.15 | 61 |
| 2010 | 3.07 | 65 |
| 2009 | 2.98 | 69 |
| 2008 | 2.93 | 71 |
| 2007 | 2.89 | 73 |
| 2006 | 3.36 | 59 |
| 2005 | 3.36 | 61 |
| 2004 | 3.39 | 58 |
| 2003 | 3.41 | 56 |
| 2002 | 3.47 | 55 |
| 2001 | 3.54 | 54 |
| 2000 | 3.62 | 50 |
| 1999 | 3.71 | 46 |
| 1998 | 3.82 | 43 |
| 1997 | 3.97 | 40 |
| 1996 | 5.03 | 14 |
| 1995 | 5.49 | 6 |
| 1994 | 5.71 | 10 |
| 1993 | 5.85 | 11 |
| 1992 | 5.88 | 12 |
| 1991 | 5.82 | 15 |
| 1990 | 5.71 | 19 |
| 1989 | 5.63 | 22 |
| 1988 | 5.62 | 26 |
| 1987 | 5.72 | 25 |
| 1986 | 3.16 | 98 |