49.91 is the one used by most sources, because
more people look it up on here than on the official state website.
Dave is trying to count ALL write ins and be uniform, even though in many states that basically means ignoring the state law. Such as Florida - the "correct" (insofar as one choice on this question can be correct) choice is no doubt 50.01%.
In some of the states where that is the case - though not Florida - the data he wants is actually not readily available, hence why the presentation is not uniform
yet. Give it some more months still.