| Year | Number of papers | % |
| 2001 | 1 | 3% |
| 2002 | 1 | 3% |
| 2003 | 0 | 0% |
| 2004 | 2 | 6% |
| 2005 | 2 | 6% |
| 2006 | 1 | 3% |
| 2007 | 2 | 6% |
| 2008 | 1 | 3% |
| 2009 | 2 | 6% |
| 2010 | 1 | 3% |
| 2011 | 6 | 18% |
| 2012 | 4 | 12% |
| 2013 | 7 | 21% |
| 2014 | 3 | 9% |
| Total | 33 | 100% |