| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2011 | 77.8 | 65 |
| 2010 | 88.73 | 39 |
| 2009 | 79.03 | 44 |
| 2008 | 81.76 | 64 |
| 2007 | 79.54 | 59 |
| 2006 | 84.24 | 49 |
| 2005 | 79.09 | 62 |
| 2004 | 80.72 | 49 |
| 2003 | 72.25 | 56 |
| 2002 | 69.32 | 65 |
| 2001 | 45.18 | 127 |
| 2000 | 44.71 | 126 |
| 1999 | 33.65 | 150 |
| 1998 | 44.5 | 118 |
| 1997 | 51.4 | 98 |
| 1996 | 56.58 | 78 |
| 1995 | 56.24 | 79 |
| 1994 | 50.69 | 87 |
| 1993 | 46.13 | 87 |
| 1992 | 44.59 | 91 |
| 1991 | 51.87 | 64 |
| 1990 | 64.22 | 49 |