One more thing that stood out as a sore thumb to me: you do not comment on the fact that the first graph (the chronologically later one) splits up the programmi

One more thing that stood out as a sore thumb to me: you do not comment on the fact that the first graph (the chronologically later one) splits up the programming languages in a different way than the second one! It won't weaken your point much to just use the same key in both graphs, but you don't do it, and you don't comment on it, which is a little sloppy. (C/C++ are two different entries in the first graph, while they are the same (adding up their scores, thus exaggerating the upwards tendency of the curve in the higher-value range of the x-axis) in the second. Something similar happened for VB.NET.)