| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 12.9 | 191 |
| 2015 | 13 | 191 |
| 2014 | 13.1 | 191 |
| 2013 | 13.1 | 191 |
| 2012 | 13.2 | 191 |
| 2011 | 13.3 | 191 |
| 2010 | 13.4 | 190 |
| 2009 | 13.4 | 191 |
| 2008 | 13.5 | 192 |
| 2007 | 13.6 | 192 |
| 2006 | 13.7 | 193 |
| 2005 | 13.8 | 193 |
| 2004 | 14 | 193 |
| 2003 | 14.2 | 193 |
| 2002 | 14.4 | 193 |
| 2001 | 14.6 | 192 |
| 2000 | 14.8 | 192 |
| 1999 | 15 | 192 |
| 1998 | 15.3 | 193 |
| 1997 | 15.6 | 193 |
| 1996 | 15.9 | 193 |
| 1995 | 16.2 | 193 |
| 1994 | 16.6 | 192 |
| 1993 | 17 | 191 |
| 1992 | 17.4 | 188 |
| 1991 | 17.9 | 186 |
| 1990 | 18.5 | 184 |
| 1989 | 19.1 | 180 |
| 1988 | 19.8 | 179 |
| 1987 | 20.5 | 179 |
| 1986 | 21.2 | 176 |