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. 2021 Sep 14;6(9):e006523. doi: 10.1136/bmjgh-2021-006523

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© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.

This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See: https://creativecommons.org/licenses/by/4.0/.

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Number of publications per type and year of publication. (Note: publications published up to 31 August 2020 only were included, hence the reduction in the number of publications in 2020 compared with 2019)