| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 11.85 | 115 |
| 2015 | 11.45 | 115 |
| 2014 | 11.08 | 115 |
| 2013 | 10.74 | 113 |
| 2012 | 10.42 | 113 |
| 2011 | 10.13 | 111 |
| 2010 | 9.85 | 109 |
| 2009 | 9.62 | 109 |
| 2008 | 9.42 | 105 |
| 2007 | 9.24 | 102 |
| 2006 | 9.06 | 99 |
| 2005 | 8.86 | 98 |
| 2004 | 8.66 | 97 |
| 2003 | 8.45 | 95 |
| 2002 | 8.23 | 93 |
| 2001 | 8.01 | 93 |
| 2000 | 7.81 | 92 |
| 1999 | 7.67 | 90 |
| 1998 | 7.55 | 90 |
| 1997 | 7.44 | 88 |
| 1996 | 7.33 | 85 |
| 1995 | 7.19 | 82 |
| 1994 | 7.12 | 81 |
| 1993 | 7.03 | 80 |
| 1992 | 6.92 | 77 |
| 1991 | 6.8 | 77 |
| 1990 | 6.68 | 75 |
| 1989 | 6.63 | 73 |
| 1988 | 6.59 | 74 |
| 1987 | 6.55 | 71 |
| 1986 | 6.51 | 70 |