Consider adding a column on coverage

[allakulov]

During an ongoing OCDS implementation, significant issues have been encountered with missing values in mapped fields. This has affected the initial usability check, likely making it less informative after data publication.

To address this, a new column on "coverage" could be added for each mapped field. This column would reflect the coverage percentage for each field, which would be a useful indication when producing usability checks before OCDS implementation. The coverage column would be optional and should be filled out only when feasible.