I remember this Gallup poll from the early 1990s.
Actually, the poll provided five choices, and gave them all in moderately theologically-technical language. Only 30% of respondents correctly chose the choice that described transubstantiation. But others chose similar-sounding descriptions of consubstantiation and similar doctrines of Real Presence, with 64% selecting one choice or other that signified the Real Presence (albeit not necessarily transubstantiation), as opposed to a merely symbolic presence.
Thus, the poll didn't show that Catholics don't generally believe in the Real Presence but rather that most Catholics DO believe in the Real Presence, but cannot identify the theological language accurately that describes Catholic belief.
That's not a good thing, but neither is it that 70% of Catholics reject the Real Presence.
sitetest
By the way, a couple of more pertinent facts. Among weekly Church-going Catholics, the belief in the Real Presence was higher, and 44% of weekly Mass-assisting Catholic chose the correct response describing transubstantiation.
As well, the poll was conducted over the telephone, and thus, folks were being asked to choose between these theological explanations verbally, over a phone, without the ability to see on paper what was being asked.
Not a very promising methodology.
sitetest