| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 79.04 | 29 |
| 2015 | 79.34 | 27 |
| 2014 | 79.55 | 27 |
| 2013 | 79.65 | 28 |
| 2012 | 81.27 | 19 |
| 2011 | 80.79 | 22 |
| 2010 | 81.19 | 20 |
| 2009 | 80.86 | 21 |
| 2008 | 80.18 | 26 |
| 2007 | 79.07 | 30 |
| 2006 | 76.57 | 40 |
| 2005 | 73.19 | 59 |
| 2004 | 72.46 | 63 |
| 2003 | 72.17 | 64 |
| 2002 | 75.64 | 48 |
| 2001 | 77.72 | 38 |
| 2000 | 76.64 | 43 |
| 1999 | 77.01 | 43 |
| 1998 | 77.93 | 40 |
| 1997 | 76.59 | 48 |
| 1996 | 76.33 | 50 |
| 1995 | 75.7 | 56 |
| 1994 | 74.56 | 63 |
| 1993 | 73.56 | 72 |
| 1992 | 71.35 | 86 |
| 1991 | 73.29 | 75 |