Table 1 Top 20 countries of publication volume
| Ranking | Count | Centrality | Year | Country | Ranking | Count | Centrality | Year | Country |
| 1 | 467 | 0.45 | 1996 | USA | 11 | 4 | 0 | 2016 | Norway |
| 2 | 34 | 0 | 2004 | Canada | 12 | 4 | 0 | 2012 | Singapore |
| 3 | 14 | 0.16 | 2008 | England | 13 | 4 | 0 | 2011 | Sweden |
| 4 | 12 | 0.01 | 2012 | Australia | 14 | 3 | 0.08 | 2018 | Finland |
| 5 | 9 | 0.02 | 2011 | South Korea | 15 | 3 | 0 | 2008 | Wales |
| 6 | 9 | 0.01 | 2014 | Italy | 16 | 2 | 0.01 | 2019 | Germany |
| 7 | 7 | 0 | 2011 | Netherlands | 17 | 1 | 0 | 2023 | Cyprus |
| 8 | 7 | 0 | 2014 | New Zealand | 18 | 1 | 0 | 2020 | Denmark |
| 9 | 5 | 0 | 2010 | Turkey | 19 | 1 | 0 | 2019 | Egypt |
| 10 | 4 | 0 | 2017 | Ireland | 20 | 1 | 0 | 2011 | Japan |