| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 77.3 | 71 |
| 2015 | 77.05 | 73 |
| 2014 | 76.78 | 73 |
| 2013 | 76.49 | 76 |
| 2012 | 77.24 | 71 |
| 2011 | 77.46 | 66 |
| 2010 | 76.62 | 73 |
| 2009 | 75.61 | 80 |
| 2008 | 76.39 | 75 |
| 2007 | 76.99 | 69 |
| 2006 | 77.49 | 66 |
| 2005 | 76.13 | 80 |
| 2004 | 74.27 | 94 |
| 2003 | 74.11 | 95 |
| 2002 | 73.94 | 99 |
| 2001 | 74.01 | 100 |
| 2000 | 74.06 | 101 |
| 1999 | 74.08 | 104 |
| 1998 | 74.12 | 106 |
| 1997 | 74.16 | 109 |
| 1996 | 74.21 | 108 |
| 1995 | 74.25 | 105 |
| 1994 | 74.25 | 111 |
| 1993 | 74.24 | 112 |
| 1992 | 74.22 | 117 |
| 1991 | 74.23 | 121 |
| 1990 | 74.32 | 123 |