| 时间 | 值 （人/平方公里） | 世界排名 |
|---|---|---|
| 2016 | 19.7 | 181 |
| 2015 | 19.6 | 181 |
| 2014 | 19.5 | 178 |
| 2013 | 19.5 | 178 |
| 2012 | 19.4 | 178 |
| 2011 | 19.3 | 177 |
| 2010 | 19.3 | 174 |
| 2009 | 19.2 | 172 |
| 2008 | 19.1 | 172 |
| 2007 | 19.1 | 172 |
| 2006 | 19 | 172 |
| 2005 | 19 | 172 |
| 2004 | 19 | 172 |
| 2003 | 19 | 172 |
| 2002 | 19 | 172 |
| 2001 | 19 | 172 |
| 2000 | 19 | 172 |
| 1999 | 18.9 | 169 |
| 1998 | 18.8 | 169 |
| 1997 | 18.7 | 168 |
| 1996 | 18.6 | 168 |
| 1995 | 18.4 | 166 |
| 1994 | 18.3 | 165 |
| 1993 | 18.2 | 164 |
| 1992 | 18 | 162 |
| 1991 | 17.9 | 163 |
| 1990 | 17.8 | 160 |
| 1989 | 17.6 | 156 |
| 1988 | 17.5 | 155 |
| 1987 | 17.4 | 155 |
| 1986 | 17.3 | 155 |