| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 52.7 | 180 |
| 2015 | 52.3 | 181 |
| 2014 | 52 | 181 |
| 2013 | 51.7 | 180 |
| 2012 | 51.3 | 183 |
| 2011 | 51 | 185 |
| 2010 | 50.9 | 185 |
| 2009 | 50.7 | 186 |
| 2008 | 50.6 | 185 |
| 2007 | 50.6 | 185 |
| 2006 | 50.5 | 185 |
| 2005 | 50.5 | 185 |
| 2004 | 50.4 | 186 |
| 2003 | 50.3 | 185 |
| 2002 | 50.2 | 184 |
| 2001 | 50.2 | 184 |
| 2000 | 50.3 | 183 |
| 1999 | 50.3 | 182 |
| 1998 | 50.4 | 181 |
| 1997 | 50.6 | 181 |
| 1996 | 50.7 | 175 |
| 1995 | 50.9 | 173 |
| 1994 | 51.1 | 170 |
| 1993 | 51.2 | 167 |
| 1992 | 51.2 | 162 |
| 1991 | 51.4 | 162 |
| 1990 | 51.7 | 157 |
| 1989 | 51.1 | 159 |
| 1988 | 50.7 | 161 |
| 1987 | 50.4 | 165 |
| 1986 | 50.1 | 174 |