| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 81.75 | 15 |
| 2015 | 82 | 14 |
| 2014 | 81.15 | 19 |
| 2013 | 80.84 | 21 |
| 2012 | 80.53 | 26 |
| 2011 | 80.55 | 25 |
| 2010 | 82.2 | 15 |
| 2009 | 81.63 | 18 |
| 2008 | 80.57 | 23 |
| 2007 | 80.42 | 22 |
| 2006 | 80.52 | 21 |
| 2005 | 80.36 | 21 |
| 2004 | 80.11 | 23 |
| 2003 | 80.36 | 22 |
| 2002 | 80.63 | 22 |
| 2001 | 81.34 | 20 |
| 2000 | 82.1 | 19 |
| 1999 | 82.1 | 19 |
| 1998 | 82.14 | 22 |
| 1997 | 82.36 | 22 |
| 1996 | 82.76 | 22 |
| 1995 | 82.06 | 22 |
| 1994 | 81.36 | 26 |
| 1993 | 79.61 | 33 |
| 1992 | 78.29 | 44 |
| 1991 | 77.52 | 51 |