| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 21.24 | 100 |
| 2015 | 22.35 | 111 |
| 2014 | 23.79 | 102 |
| 2013 | 24.85 | 100 |
| 2012 | 26.03 | 96 |
| 2011 | 27.17 | 88 |
| 2010 | 27.38 | 89 |
| 2009 | 25.59 | 97 |
| 2008 | 27.33 | 92 |
| 2007 | 27.12 | 93 |
| 2006 | 27.68 | 92 |
| 2005 | 28.47 | 83 |
| 2004 | 28.63 | 80 |
| 2003 | 26.96 | 89 |
| 2002 | 26.37 | 94 |
| 2001 | 26.59 | 94 |
| 2000 | 26.75 | 91 |
| 1999 | 25.11 | 100 |
| 1998 | 25.14 | 99 |
| 1997 | 25.71 | 99 |
| 1996 | 25.55 | 100 |
| 1995 | 27.53 | 93 |
| 1994 | 40 | 25 |
| 1993 | 41.61 | 19 |
| 1992 | 38.7 | 31 |
| 1991 | 36.16 | 38 |
| 1990 | 38.69 | 29 |
| 1989 | 42.67 | 16 |
| 1988 | 43.65 | 13 |
| 1987 | 45.88 | 10 |
| 1986 | 45.16 | 10 |