| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 83.75 | 23 |
| 2015 | 83.85 | 22 |
| 2014 | 83.94 | 21 |
| 2013 | 84.22 | 19 |
| 2012 | 84.27 | 19 |
| 2011 | 84.3 | 20 |
| 2010 | 84.32 | 21 |
| 2009 | 84.66 | 19 |
| 2008 | 84.26 | 20 |
| 2007 | 84.69 | 18 |
| 2006 | 85.02 | 18 |
| 2005 | 85.3 | 19 |
| 2004 | 85.24 | 18 |
| 2003 | 85.12 | 18 |
| 2002 | 84.95 | 19 |
| 2001 | 84.92 | 19 |
| 2000 | 84.82 | 19 |
| 1999 | 84.71 | 19 |
| 1998 | 81.26 | 55 |
| 1997 | 83.1 | 36 |
| 1996 | 84.36 | 26 |
| 1995 | 83.32 | 40 |
| 1994 | 82.03 | 48 |
| 1993 | 82.18 | 47 |
| 1992 | 81.83 | 51 |
| 1991 | 81.49 | 53 |
| 1990 | 81.14 | 57 |