| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 80.4 | 45 |
| 2015 | 80.46 | 44 |
| 2014 | 80.54 | 43 |
| 2013 | 81.23 | 37 |
| 2012 | 81.59 | 35 |
| 2011 | 80.76 | 42 |
| 2010 | 81.96 | 31 |
| 2009 | 82.48 | 30 |
| 2008 | 82.93 | 28 |
| 2007 | 80.91 | 44 |
| 2006 | 80.71 | 49 |
| 2005 | 81.12 | 43 |
| 2004 | 81.39 | 44 |
| 2003 | 80.69 | 50 |
| 2002 | 80.69 | 54 |
| 2001 | 81.13 | 53 |
| 2000 | 81.54 | 46 |
| 1999 | 81.92 | 45 |
| 1998 | 82.67 | 40 |
| 1997 | 81.07 | 53 |
| 1996 | 81.43 | 53 |
| 1995 | 81.77 | 54 |
| 1994 | 80.99 | 58 |
| 1993 | 81.19 | 56 |
| 1992 | 79.94 | 72 |
| 1991 | 78.58 | 82 |
| 1990 | 79.28 | 79 |