| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 54.7 | 168 |
| 2015 | 54.4 | 168 |
| 2014 | 54.1 | 170 |
| 2013 | 53.9 | 170 |
| 2012 | 53.6 | 171 |
| 2011 | 53.4 | 173 |
| 2010 | 53.3 | 174 |
| 2009 | 53 | 175 |
| 2008 | 52.9 | 175 |
| 2007 | 52.7 | 175 |
| 2006 | 52.6 | 172 |
| 2005 | 52.5 | 172 |
| 2004 | 52.4 | 172 |
| 2003 | 52.2 | 172 |
| 2002 | 52.1 | 171 |
| 2001 | 52.1 | 172 |
| 2000 | 52.1 | 167 |
| 1999 | 52.1 | 164 |
| 1998 | 52.2 | 163 |
| 1997 | 52.4 | 159 |
| 1996 | 52.5 | 154 |
| 1995 | 52.7 | 151 |
| 1994 | 52.8 | 145 |
| 1993 | 52.8 | 140 |
| 1992 | 52.7 | 139 |
| 1991 | 52.8 | 137 |
| 1990 | 53 | 130 |
| 1989 | 52.9 | 133 |
| 1988 | 52.8 | 134 |
| 1987 | 52.9 | 133 |
| 1986 | 53.1 | 132 |