| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 80.7 | 42 |
| 2015 | 80.63 | 42 |
| 2014 | 80.54 | 44 |
| 2013 | 80.5 | 44 |
| 2012 | 80.44 | 45 |
| 2011 | 80.36 | 46 |
| 2010 | 80.3 | 49 |
| 2009 | 80.25 | 48 |
| 2008 | 80.21 | 49 |
| 2007 | 80.21 | 51 |
| 2006 | 80.23 | 51 |
| 2005 | 80.41 | 50 |
| 2004 | 80.6 | 52 |
| 2003 | 80.8 | 49 |
| 2002 | 81.01 | 51 |
| 2001 | 81.23 | 52 |
| 2000 | 81.47 | 47 |
| 1999 | 81.72 | 46 |
| 1998 | 81.99 | 44 |
| 1997 | 82.26 | 43 |
| 1996 | 82.54 | 42 |
| 1995 | 82.82 | 43 |
| 1994 | 83.17 | 40 |
| 1993 | 83.51 | 40 |
| 1992 | 83.83 | 39 |
| 1991 | 84.13 | 38 |
| 1990 | 84.42 | 34 |