| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 31.81 | 35 |
| 2014 | 33.86 | 34 |
| 2013 | 36.67 | 35 |
| 2012 | 36.14 | 35 |
| 2011 | 35.17 | 38 |
| 2010 | 39.5 | 29 |
| 2009 | 43.09 | 25 |
| 2008 | 37.64 | 36 |
| 2007 | 43.38 | 27 |
| 2006 | 41.16 | 30 |
| 2005 | 42.92 | 27 |
| 2004 | 32.55 | 34 |
| 1999 | 31.52 | 31 |
| 1998 | 34.01 | 31 |
| 1997 | 36.89 | 24 |
| 1996 | 39.8 | 23 |
| 1995 | 40.42 | 23 |
| 1994 | 32.19 | 30 |
| 1993 | 55.62 | 9 |
| 1992 | 60.53 | 7 |
| 1991 | 52.03 | 8 |
| 1990 | 48.06 | 11 |
| 1989 | 40.44 | 18 |
| 1988 | 33.93 | 22 |
| 1987 | 28.08 | 27 |
| 1986 | 25.47 | 32 |