On SO, how many unsuccessful close votes have ever been cast on questions with a total of at least two closevotes?
How are they distributed? (Dupe, Off-topic, NaRQ, ....)
How has their number and distribution developed over time?
How has the ratio of new questions to closed questions to unsuccesfully closed questions developed over time?
Has the number of unsuccessfully closevoted questions grown with the overall number of questions?
This is something only the devs can answer, if at all. (Related feature request here.)