| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 14.1 | 99 |
| 2014 | 12.58 | 120 |
| 2013 | 12.83 | 129 |
| 2012 | 13.16 | 128 |
| 2011 | 13.31 | 129 |
| 2010 | 12.53 | 130 |
| 2009 | 12.52 | 126 |
| 2008 | 13.38 | 124 |
| 2007 | 15.3 | 111 |
| 2006 | 14.92 | 107 |
| 2005 | 14.63 | 107 |
| 2004 | 16.44 | 90 |
| 2003 | 14.35 | 100 |
| 2002 | 14.37 | 96 |
| 2001 | 15.07 | 90 |
| 2000 | 12.86 | 97 |
| 1999 | 14.39 | 85 |
| 1998 | 16.51 | 72 |
| 1997 | 16.81 | 67 |
| 1996 | 24.04 | 36 |
| 1995 | 26.3 | 34 |
| 1994 | 20.43 | 51 |
| 1993 | 24.31 | 36 |
| 1992 | 11.11 | 85 |
| 1991 | 8.93 | 93 |
| 1990 | 9.82 | 83 |
| 1989 | 8.82 | 88 |
| 1988 | 7.47 | 98 |