Some interesting oddities - for instance 3 productions of H VI part 2 on it's own, and no productions of any of the three between 1905 and the late 70s.
Yeah, I suspect that's because the histories was rolled up into things like "The Plantagenets" and other adaptations. The script I used to scrape the data off the RSC archive only pulls complete plays by name. I suppose I could produce a list of all the Henry adaptations and include those as well.
I did a similar job for the Proms a few years ago, and plotted out the rise and fall of various composers (out with Haydn! In with Shostakovich!). Some visualisation of what particular directors were doing would be interesting, too.