That's an amazing addition! Once I read about Simpson's paradox[0], couldn't help but seeing it or suspecting it everywhere. Luckily, it is not a true paradox, and it can resolved if underlying data is available and not just summary statistics.
I recommend putting together the Quintet in one image, so that the original 4 charts, plus the new one are all visible and interpretable together. It will be learning aid for decades to come.