| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 78.32 | 9 |
| 2015 | 78.19 | 10 |
| 2014 | 78.07 | 10 |
| 2013 | 78.1 | 10 |
| 2012 | 78.1 | 11 |
| 2011 | 78.17 | 11 |
| 2010 | 78.01 | 11 |
| 2009 | 79.29 | 11 |
| 2008 | 79.92 | 8 |
| 2007 | 80.41 | 9 |
| 2006 | 80.83 | 7 |
| 2005 | 82.07 | 4 |
| 2004 | 83.24 | 3 |
| 2003 | 80.47 | 7 |
| 2002 | 77.1 | 12 |
| 2001 | 73.42 | 17 |
| 2000 | 71.24 | 25 |
| 1999 | 67.01 | 33 |
| 1998 | 67.78 | 33 |
| 1997 | 68.61 | 29 |
| 1996 | 69.33 | 28 |
| 1995 | 69.76 | 27 |
| 1994 | 70.09 | 27 |
| 1993 | 69.32 | 28 |
| 1992 | 69.29 | 28 |
| 1991 | 69.21 | 28 |