| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 79.26 | 52 |
| 2015 | 79.26 | 51 |
| 2014 | 79.26 | 51 |
| 2013 | 79.25 | 51 |
| 2012 | 79.25 | 54 |
| 2011 | 79.26 | 55 |
| 2010 | 79.28 | 55 |
| 2009 | 79.3 | 56 |
| 2008 | 79.33 | 57 |
| 2007 | 79.37 | 56 |
| 2006 | 79.41 | 56 |
| 2005 | 79.45 | 57 |
| 2004 | 79.5 | 55 |
| 2003 | 79.55 | 57 |
| 2002 | 79.6 | 60 |
| 2001 | 79.66 | 62 |
| 2000 | 79.72 | 64 |
| 1999 | 79.78 | 63 |
| 1998 | 79.85 | 63 |
| 1997 | 79.93 | 67 |
| 1996 | 80.01 | 70 |
| 1995 | 80.1 | 69 |
| 1994 | 80.19 | 70 |
| 1993 | 80.3 | 68 |
| 1992 | 80.76 | 62 |
| 1991 | 80.76 | 62 |
| 1990 | 80.74 | 62 |