| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2014 | 3.9 | 159 |
| 2013 | 5.8 | 165 |
| 2012 | 5.66 | 167 |
| 2011 | 5.94 | 168 |
| 2010 | 4.12 | 175 |
| 2009 | 4.7 | 172 |
| 2008 | 4.89 | 170 |
| 2007 | 5.59 | 169 |
| 2006 | 4.11 | 172 |
| 2005 | 4.6 | 168 |
| 2004 | 5 | 154 |
| 2003 | 5.26 | 150 |
| 2002 | 5.33 | 149 |
| 2001 | 4.94 | 143 |
| 2000 | 4.82 | 140 |
| 1999 | 5.8 | 135 |
| 1998 | 6.17 | 132 |
| 1997 | 6.12 | 133 |
| 1996 | 9.5 | 114 |
| 1995 | 8.79 | 119 |
| 1994 | 11.17 | 94 |
| 1993 | 10.19 | 101 |
| 1992 | 9.69 | 95 |
| 1991 | 9.14 | 90 |
| 1990 | 8.03 | 100 |
| 1989 | 6.83 | 105 |
| 1988 | 6.33 | 106 |
| 1987 | 6.84 | 98 |
| 1986 | 5.06 | 107 |