Joss thinks this survey is far more representative.
However it’s less recent (graph at the start goes up to 2016) and the wording of the question is really ambiguous:
Please think about a transgender woman - that is a man who has gone through all or part of a process to become a woman. How comfortable or uncomfortable would you be for a transgender woman to use female public toilets?
“all or part of a process”
It very much does not specify that this can include male-bodied people with fully-functioning penises, who as we all now realise probably make up 80% of “transwomen”.
I bet if this survey had spelled that out the figures would be different...