| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 78.04 | 32 |
| 2015 | 78.03 | 33 |
| 2014 | 78.06 | 33 |
| 2013 | 78.81 | 30 |
| 2012 | 78.52 | 31 |
| 2011 | 78.74 | 29 |
| 2010 | 78.96 | 29 |
| 2009 | 79.16 | 29 |
| 2008 | 80.73 | 21 |
| 2007 | 80.45 | 21 |
| 2006 | 80.56 | 20 |
| 2005 | 81.61 | 16 |
| 2004 | 81.15 | 16 |
| 2003 | 81.35 | 18 |
| 2002 | 82.41 | 18 |
| 2001 | 82.81 | 17 |
| 2000 | 83.22 | 15 |
| 1999 | 83.24 | 17 |
| 1998 | 84.14 | 16 |
| 1997 | 83.13 | 21 |
| 1996 | 84.8 | 17 |
| 1995 | 84.37 | 19 |
| 1994 | 85.1 | 18 |
| 1993 | 85.94 | 16 |
| 1992 | 84.9 | 17 |
| 1991 | 86.85 | 13 |