| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 9.95 | 100 |
| 2015 | 9.7 | 100 |
| 2014 | 9.52 | 99 |
| 2013 | 9.43 | 99 |
| 2012 | 9.4 | 102 |
| 2011 | 9.4 | 103 |
| 2010 | 9.39 | 104 |
| 2009 | 9.34 | 103 |
| 2008 | 9.28 | 102 |
| 2007 | 9.21 | 100 |
| 2006 | 9.13 | 102 |
| 2005 | 9.06 | 102 |
| 2004 | 8.96 | 102 |
| 2003 | 8.87 | 101 |
| 2002 | 8.77 | 101 |
| 2001 | 8.68 | 101 |
| 2000 | 8.59 | 103 |
| 1999 | 8.51 | 104 |
| 1998 | 8.43 | 103 |
| 1997 | 8.34 | 104 |
| 1996 | 8.22 | 104 |
| 1995 | 8.06 | 104 |
| 1994 | 7.88 | 101 |
| 1993 | 7.66 | 98 |
| 1992 | 7.43 | 92 |
| 1991 | 7.19 | 88 |
| 1990 | 6.95 | 85 |
| 1989 | 6.75 | 79 |
| 1988 | 6.56 | 71 |
| 1987 | 6.4 | 67 |
| 1986 | 6.25 | 60 |