| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2012 | 14.59 | 115 |
| 2011 | 19.11 | 85 |
| 2010 | 15.74 | 101 |
| 2009 | 12.21 | 131 |
| 2008 | 15.4 | 106 |
| 2007 | 15.46 | 108 |
| 2006 | 15.14 | 105 |
| 2005 | 17.79 | 89 |
| 2004 | 19.38 | 74 |
| 2003 | 17.05 | 80 |
| 2002 | 13.91 | 99 |
| 2001 | 12.01 | 115 |
| 2000 | 12.08 | 107 |
| 1999 | 12.21 | 105 |
| 1998 | 10.83 | 108 |
| 1997 | 9.14 | 121 |
| 1996 | 8.5 | 122 |
| 1995 | 9.1 | 113 |
| 1994 | 8.73 | 110 |
| 1993 | 6.53 | 120 |
| 1992 | 6.06 | 117 |
| 1991 | 4.1 | 119 |
| 1990 | 5.45 | 114 |
| 1989 | 5.34 | 112 |
| 1988 | 5.52 | 109 |
| 1987 | 5.74 | 107 |
| 1986 | 5.24 | 105 |