| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 78.63 | 30 |
| 2015 | 78.4 | 30 |
| 2014 | 78.31 | 30 |
| 2013 | 78.1 | 34 |
| 2012 | 78.55 | 30 |
| 2011 | 78.81 | 28 |
| 2010 | 79.21 | 27 |
| 2009 | 79.49 | 27 |
| 2008 | 79.9 | 28 |
| 2007 | 80.29 | 25 |
| 2006 | 80.25 | 24 |
| 2005 | 78.63 | 29 |
| 2004 | 78.26 | 32 |
| 2003 | 77.8 | 32 |
| 2002 | 78.06 | 36 |
| 2001 | 78.43 | 36 |
| 2000 | 79.05 | 34 |
| 1999 | 79.86 | 28 |
| 1998 | 79.72 | 30 |
| 1997 | 80.17 | 30 |
| 1996 | 80.09 | 30 |
| 1995 | 80.07 | 33 |
| 1994 | 80.47 | 31 |
| 1993 | 80.18 | 31 |
| 1992 | 81.07 | 29 |
| 1991 | 80.74 | 30 |