Poll results aren't worth much, because the question is too vague and there are not enough measurable qualities.
I'm not sure I would agree that INTPs are the most emotionally stable type. Personally, I feel my emotions quite strongly at times (music, for instance). They are very invigorating.
If you truly mean "the highs and lows" of emotion, then all types experience them near equally. We're all human.
If you are asking which type is most expressive with emotions, maybe ESF? Not sure on that one.