| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 78.24 | 10 |
| 2015 | 78.59 | 9 |
| 2014 | 78.81 | 9 |
| 2013 | 78.97 | 9 |
| 2012 | 78.35 | 10 |
| 2011 | 79.08 | 10 |
| 2010 | 79.32 | 10 |
| 2009 | 79.54 | 10 |
| 2008 | 79.64 | 10 |
| 2007 | 79.76 | 10 |
| 2006 | 79.94 | 9 |
| 2005 | 79.99 | 8 |
| 2004 | 79.52 | 8 |
| 2003 | 78.51 | 9 |
| 2002 | 77.43 | 11 |
| 2001 | 76.3 | 13 |
| 2000 | 77.23 | 11 |
| 1999 | 74.1 | 18 |
| 1998 | 74.97 | 16 |
| 1997 | 75.68 | 13 |
| 1996 | 76.37 | 15 |
| 1995 | 76.5 | 14 |
| 1994 | 76.55 | 14 |
| 1993 | 76.55 | 15 |
| 1992 | 76.59 | 16 |
| 1991 | 76.45 | 17 |