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. 2022 Aug 12;30(1):63–67. doi: 10.1177/17579759221113276

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© The Author(s) 2022

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Figure 1. — Global distribution of studies with original data (N = 67), (a) based on level of income, (b) based on geographical region. Classifications are rooted in the World Bank classification for the 2020–2021 fiscal year. (c) Number of studies based on countries according to the level of income on the bar chart. Maps were created by Datawrapper ©.