Count authors for each distinct value of total AR participations
Count total authors for each cumulated total assessment report
Add script to count authors per cumulated assessment report to answers
Count total RESP authors per total assessment reports
Add '+' after total AR participations to make cumulated AR title

The only discrepancy with the categories described in the
documentation is '5+' instead of '5', which is hard to
understand in the context of only 5 assessment reports.
Add explicit ORDER BY clause

Even if the order in results was the same without it.
Count total RESP authors per cumulated AR (1+, 2+, 3+, 4+, 5+)
Add first answer for question2
Rename count-*.sql to count-multiple{-resp}-participations.sql
Simplify selection of records '1', '2',..., '5' for cumulated AR

Instead of duplicating the whole selection twice, once to get the
list of distinct cumulated AR, once to count the authors in each
of the cumulated categories with a join using the greater than
or equal operator in the comparison, the list of values from 1 to 5
is directly retrieved from the identifiers of assessment reports,
which happen to vary in the same way from 1 to 5.
Count multiple participations by WMO country group