This is to answer the question - How many were marked ready in column X during this time period? And, how long did it take to get from point A to point B, where either of those points may not be mapped directly to creation date, in-progress date, accepted date, etc. (For example, if we had multiple columns mapped to in-progress)
On an individual basis this would need to be retrieved from the Revision History of the story. There currently is no app or chart in the application where this can be displayed in a chart or report format.