| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2013 | 52.9 | 72 |
| 2012 | 45.73 | 85 |
| 2011 | 35.94 | 114 |
| 2010 | 32.16 | 123 |
| 2009 | 37.42 | 106 |
| 2008 | 31.67 | 117 |
| 2007 | 33.69 | 111 |
| 2006 | 31.59 | 112 |
| 2005 | 23.69 | 126 |
| 2004 | 22.97 | 126 |
| 2003 | 24.28 | 123 |
| 2002 | 18.61 | 135 |
| 2001 | 19.68 | 130 |
| 2000 | 19.84 | 124 |
| 1999 | 19.91 | 121 |
| 1998 | 19.42 | 120 |
| 1997 | 21.57 | 114 |
| 1996 | 20.41 | 117 |
| 1995 | 26.01 | 97 |
| 1994 | 30.05 | 87 |
| 1993 | 28.3 | 90 |
| 1992 | 29.76 | 85 |
| 1991 | 34.38 | 71 |
| 1990 | 31.05 | 72 |
| 1989 | 28.42 | 77 |
| 1988 | 34.54 | 60 |
| 1987 | 36.97 | 53 |
| 1986 | 43.05 | 44 |