| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.1 | 8 |
| 2015 | 5.21 | 8 |
| 2014 | 5.31 | 9 |
| 2013 | 5.41 | 12 |
| 2012 | 5.49 | 11 |
| 2011 | 5.55 | 10 |
| 2010 | 5.58 | 9 |
| 2009 | 5.6 | 9 |
| 2008 | 5.63 | 11 |
| 2007 | 5.65 | 10 |
| 2006 | 5.68 | 9 |
| 2005 | 5.71 | 11 |
| 2004 | 5.74 | 13 |
| 2003 | 5.71 | 12 |
| 2002 | 5.63 | 10 |
| 2001 | 5.48 | 11 |
| 2000 | 5.3 | 10 |
| 1999 | 5.12 | 14 |
| 1998 | 5.02 | 13 |
| 1997 | 5.07 | 14 |
| 1996 | 5.22 | 10 |
| 1995 | 5.43 | 7 |
| 1994 | 5.62 | 11 |
| 1993 | 5.72 | 13 |
| 1992 | 5.7 | 14 |
| 1991 | 5.56 | 19 |
| 1990 | 5.36 | 28 |
| 1989 | 5.19 | 29 |
| 1988 | 5.14 | 37 |
| 1987 | 5.23 | 33 |
| 1986 | 5.47 | 33 |