| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 1.7 | 42 |
| 2015 | 1.63 | 46 |
| 2014 | 1.56 | 48 |
| 2013 | 1.52 | 51 |
| 2012 | 1.51 | 51 |
| 2011 | 1.53 | 54 |
| 2010 | 1.57 | 56 |
| 2009 | 1.6 | 55 |
| 2008 | 1.6 | 57 |
| 2007 | 1.55 | 58 |
| 2006 | 1.48 | 61 |
| 2005 | 1.41 | 65 |
| 2004 | 1.38 | 65 |
| 2003 | 1.34 | 64 |
| 2002 | 1.33 | 68 |
| 2001 | 1.34 | 69 |
| 2000 | 1.3 | 70 |
| 1999 | 1.3 | 73 |
| 1998 | 1.52 | 66 |
| 1997 | 2.07 | 47 |
| 1996 | 2.85 | 17 |
| 1995 | 3.83 | 7 |
| 1994 | 4.77 | 6 |
| 1993 | 5.41 | 5 |
| 1992 | 5.45 | 5 |
| 1991 | 4.97 | 4 |
| 1990 | 4.18 | 4 |
| 1989 | 3.42 | 10 |
| 1988 | 2.78 | 24 |
| 1987 | 2.48 | 41 |
| 1986 | 2.43 | 43 |