| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 1.28 | 1 |
| 2015 | 1.2 | 1 |
| 2014 | 1.16 | 1 |
| 2013 | 1.1 | 1 |
| 2012 | 1.02 | 1 |
| 2011 | 0.95 | 1 |
| 2010 | 0.87 | 1 |
| 2009 | 0.88 | 1 |
| 2008 | 0.9 | 1 |
| 2007 | 0.95 | 1 |
| 2006 | 1.02 | 1 |
| 2005 | 1.14 | 1 |
| 2004 | 1.18 | 1 |
| 2003 | 1.23 | 1 |
| 2002 | 1.31 | 1 |
| 2001 | 1.4 | 1 |
| 2000 | 1.5 | 1 |
| 1999 | 1.51 | 1 |
| 1998 | 1.49 | 1 |
| 1997 | 1.47 | 1 |
| 1996 | 1.46 | 1 |
| 1995 | 1.47 | 1 |
| 1994 | 1.52 | 1 |
| 1993 | 1.58 | 1 |
| 1992 | 1.64 | 1 |
| 1991 | 1.7 | 1 |
| 1990 | 1.75 | 1 |
| 1989 | 1.76 | 1 |
| 1988 | 1.76 | 1 |
| 1987 | 1.75 | 1 |
| 1986 | 1.77 | 1 |