| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 14.1 | 184 |
| 2015 | 14 | 185 |
| 2014 | 13.8 | 186 |
| 2013 | 13.7 | 187 |
| 2012 | 13.5 | 188 |
| 2011 | 13.4 | 190 |
| 2010 | 13.3 | 191 |
| 2009 | 13.2 | 193 |
| 2008 | 13.3 | 193 |
| 2007 | 13.3 | 193 |
| 2006 | 13.5 | 194 |
| 2005 | 13.6 | 194 |
| 2004 | 13.9 | 194 |
| 2003 | 14.3 | 192 |
| 2002 | 14.7 | 191 |
| 2001 | 15.2 | 191 |
| 2000 | 15.7 | 190 |
| 1999 | 16.1 | 189 |
| 1998 | 16.5 | 189 |
| 1997 | 16.9 | 189 |
| 1996 | 17.4 | 188 |
| 1995 | 17.9 | 183 |
| 1994 | 18.4 | 181 |
| 1993 | 19 | 179 |
| 1992 | 19.6 | 176 |
| 1991 | 20 | 175 |
| 1990 | 20.3 | 176 |
| 1989 | 20.7 | 174 |
| 1988 | 21 | 173 |
| 1987 | 21.2 | 174 |
| 1986 | 21.4 | 174 |