I'm not saying any of this data is wrong but I'm not sure there's any correlation between pedestrian deaths generally and deaths of children in this way. Most of the children hurt/killed in this manner are probably in driveways, parking lots, subdivisions etc. while I would expect most pedestrian deaths to be in more business district type areas, crossing the street, that sort of thing. I would also expect most child deaths to be a result of not seeing them, and most pedestrian deaths to be a result of speed - hence much fewer [adult] pedestrian deaths in driveways.

So I wouldn't expect a rise in pedestrian deaths (particularly over a very short 2 year period which could just be an aberration in the data) to necessarily mean there was a similar rise in child deaths if they happen in fundamentally different circumstances for different reasons.