I am getting close to cynical toward most polling results. One comment in the linked article, noting that one recent study found 1/3 believe in the real presence, while this one found 2/3, said this:
" it is important to look at how questions relating to belief in the Eucharist are phrased, citing the difference in wording of both studies as a “large part of the reason for the discrepancy.”
Because of this, one can see how radical differences can be found in polling results, intentionally, by different agencies wanting different results. “Science” is not as impersonal and unbiased as one might wish.
Bottom line, though, stands. Any deviation from 100% of adult Catholics believing in the Real Presence, is a matter of concern.