| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 79.12 | 160 |
| 2015 | 80.11 | 161 |
| 2014 | 81.29 | 162 |
| 2013 | 82.6 | 163 |
| 2012 | 83.99 | 164 |
| 2011 | 85.29 | 165 |
| 2010 | 86.41 | 168 |
| 2009 | 87.62 | 170 |
| 2008 | 88.65 | 174 |
| 2007 | 89.5 | 174 |
| 2006 | 90.25 | 173 |
| 2005 | 90.93 | 174 |
| 2004 | 91.61 | 174 |
| 2003 | 92.19 | 173 |
| 2002 | 92.61 | 174 |
| 2001 | 92.82 | 173 |
| 2000 | 92.75 | 174 |
| 1999 | 93.03 | 170 |
| 1998 | 93.17 | 168 |
| 1997 | 93.18 | 166 |
| 1996 | 93.1 | 164 |
| 1995 | 92.92 | 164 |
| 1994 | 93.3 | 163 |
| 1993 | 93.72 | 158 |
| 1992 | 94.12 | 159 |
| 1991 | 94.41 | 161 |
| 1990 | 94.51 | 159 |
| 1989 | 95.18 | 156 |
| 1988 | 95.75 | 155 |
| 1987 | 96.17 | 155 |
| 1986 | 96.46 | 157 |