| 时间 | 值 （人/平方公里） | 世界排名 |
|---|---|---|
| 2016 | 20.9 | 180 |
| 2015 | 20.7 | 180 |
| 2014 | 20.4 | 177 |
| 2013 | 20.1 | 177 |
| 2012 | 19.8 | 176 |
| 2011 | 19.4 | 175 |
| 2010 | 19.1 | 176 |
| 2009 | 18.7 | 175 |
| 2008 | 18.4 | 174 |
| 2007 | 18 | 174 |
| 2006 | 17.6 | 173 |
| 2005 | 17.2 | 173 |
| 2004 | 16.8 | 174 |
| 2003 | 15.7 | 178 |
| 2002 | 15.2 | 178 |
| 2001 | 14.8 | 177 |
| 2000 | 14.4 | 178 |
| 1999 | 14 | 176 |
| 1998 | 13.6 | 176 |
| 1997 | 13.3 | 175 |
| 1996 | 13 | 175 |
| 1995 | 12.9 | 173 |
| 1994 | 13 | 172 |
| 1993 | 11.2 | 180 |
| 1992 | 11.4 | 177 |
| 1991 | 11.5 | 175 |
| 1990 | 11.5 | 172 |
| 1989 | 11.3 | 170 |
| 1988 | 11.1 | 170 |
| 1987 | 10.7 | 170 |
| 1986 | 10.3 | 170 |