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 | 1999 | 0 |
| Non-citable documents | 2000 | 0 |
| Non-citable documents | 2001 | 0 |
| Non-citable documents | 2002 | 0 |
| Non-citable documents | 2003 | 0 |
| Non-citable documents | 2004 | 0 |
| Non-citable documents | 2005 | 0 |
| Non-citable documents | 2006 | 4 |
| Non-citable documents | 2007 | 4 |
| Non-citable documents | 2008 | 4 |
| Non-citable documents | 2009 | 3 |
| Non-citable documents | 2010 | 5 |
| Non-citable documents | 2011 | 6 |
| Non-citable documents | 2012 | 7 |
| Non-citable documents | 2013 | 9 |
| Non-citable documents | 2014 | 12 |
| Non-citable documents | 2015 | 11 |
| Non-citable documents | 2016 | 10 |
| Non-citable documents | 2017 | 10 |
| Non-citable documents | 2018 | 13 |
| Non-citable documents | 2019 | 14 |
| Non-citable documents | 2020 | 14 |
| Non-citable documents | 2021 | 19 |
| Citable documents | 1999 | 56 |
| Citable documents | 2000 | 53 |
| Citable documents | 2001 | 55 |
| Citable documents | 2002 | 58 |
| Citable documents | 2003 | 69 |
| Citable documents | 2004 | 49 |
| Citable documents | 2005 | 26 |
| Citable documents | 2006 | 16 |
| Citable documents | 2007 | 58 |
| Citable documents | 2008 | 107 |
| Citable documents | 2009 | 120 |
| Citable documents | 2010 | 118 |
| Citable documents | 2011 | 115 |
| Citable documents | 2012 | 132 |
| Citable documents | 2013 | 131 |
| Citable documents | 2014 | 126 |
| Citable documents | 2015 | 121 |
| Citable documents | 2016 | 144 |
| Citable documents | 2017 | 147 |
| Citable documents | 2018 | 145 |
| Citable documents | 2019 | 125 |
| Citable documents | 2020 | 137 |
| Citable documents | 2021 | 160 |