| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 76.23 | 82 |
| 2015 | 76.19 | 81 |
| 2014 | 76.12 | 81 |
| 2013 | 76.03 | 82 |
| 2012 | 75.84 | 84 |
| 2011 | 75.55 | 85 |
| 2010 | 75.17 | 89 |
| 2009 | 74.75 | 89 |
| 2008 | 74.22 | 97 |
| 2007 | 73.65 | 101 |
| 2006 | 73.19 | 103 |
| 2005 | 72.9 | 107 |
| 2004 | 72.87 | 110 |
| 2003 | 73.07 | 107 |
| 2002 | 73.4 | 108 |
| 2001 | 73.72 | 104 |
| 2000 | 73.92 | 104 |
| 1999 | 74.01 | 106 |
| 1998 | 73.98 | 108 |
| 1997 | 73.94 | 112 |
| 1996 | 74.02 | 110 |
| 1995 | 74.24 | 106 |
| 1994 | 74.59 | 106 |
| 1993 | 75.04 | 104 |
| 1992 | 75.52 | 104 |
| 1991 | 75.91 | 100 |
| 1990 | 76.65 | 102 |