Typology and distribution of costs (number and estimates) recorded in the starting dataset according to their reliability (“high” versus “low”) and their implementation (“potential” versus “observed”). We present both cost figures (total cumulative costs in 2017-equivalent US$ million for 1970–2019) and number of expanded cost entries as well as their specific proportion for each official region. Implementation states — at the time of the estimation — whether the reported cost was actually “observed” (i.e., cost actually incurred) or “potential” (i.e. not incurred but expected cost). Method reliability assesses the methodological approach used for cost estimation as of (i) “high” reliability if either provided by officially pre-assessed materials (peer-reviewed articles and official reports) or the estimation method was documented, repeatable and/or traceable if provided by other grey literature, or (ii) “low” reliability if not.