Not every article in a journal is considered primary research and therefore "citable", this chart shows the ratio of a journal's articles including substantial research (research articles, conference papers and reviews) in three year windows vs. those documents other than research articles, reviews and conference papers.
| Documents | Year | Value |
| Non-citable documents | 2006 | 2 |
| Non-citable documents | 2007 | 4 |
| Non-citable documents | 2008 | 5 |
| Non-citable documents | 2009 | 5 |
| Non-citable documents | 2010 | 7 |
| Non-citable documents | 2011 | 8 |
| Non-citable documents | 2012 | 6 |
| Non-citable documents | 2013 | 6 |
| Non-citable documents | 2014 | 6 |
| Non-citable documents | 2015 | 10 |
| Non-citable documents | 2016 | 8 |
| Citable documents | 2006 | 167 |
| Citable documents | 2007 | 206 |
| Citable documents | 2008 | 333 |
| Citable documents | 2009 | 225 |
| Citable documents | 2010 | 331 |
| Citable documents | 2011 | 295 |
| Citable documents | 2012 | 236 |
| Citable documents | 2013 | 282 |
| Citable documents | 2014 | 232 |
| Citable documents | 2015 | 355 |
| Citable documents | 2016 | 190 |