| Year | Volume | Number |
|---|---|---|
| 2016 | 21 | 1 2 3 4 |
| 2015 | 20 | 1 2 3 4 |
| 2014 | 19 | 1 2 3 4 |
| 2013 | 18 | 1 2 3 4 |
| 2012 | 17 | 1 2 3 |
| 2011 | 16 | 1 2 3 |
| 2010 | 15 | 1 2 3 |
| 2009 | 14 | 1 2 3 |
| 2008 | 13 | 1 2 3 |
| 2007 | 12 | 1 2 3 |
| 2006 | 11 | 1 2 3 |
| 2005 | 10 | 1 2 3 |
| 2004 | 9 | 1 2 3 |
| 2003 | 8 | 1 2 3 |
| 2002 | 7 | 1 2 special issue |
| 2001 | 6 | 1 2 |
| 2000 | 5 | 1 2 |
| 1999 | 4 | 1 2 |
| 1998 | 3 | 1 2 |
| 1997 | 2 | 1 2 |
