Consider reimplementing multi-field statistics in terms of event count percents
Percentual values of multivalue fields (Categories, Tags, IPs, ...) now reflect only relative ratio of calculated parts - resulting sum is always 100%, however that is a value of questional meaning. We could provide percentual values in terms of events - like 80% of events contains category A, 60% category B, 40% category C, summing to 180%. This reflects current info - relative ration, but also adds information about ratio to number of events and adds more meaning to percentual values.
However, this might need always calculating event summary for the query - either in one more complex db query, or in separate query, which might mean two queries per statistics.
Bonus for this would be #6310.