My own feelings on the matter are that if you don't know what prior to have, compute worst-case bounds.

In this case, the model that maximizes the probability of seeing this data is that each answer is 15% likely to be 1, 22% likely to be 2, 21% likely to be 3, 24% likely to be 4, and 18% likely to be 5. We can compute the probability of seeing this data under this model, and also under the "all answers are equally likely" model, and conclude that our worst-case model makes us only 3.61 times as likely to see this data.

In particular, any other hypothesis you might have can only receive this little evidence, relative to the uniform distribution hypothesis; and I believe in close-to-uniformity enough that I'm not going to be swayed by what is fewer than 2 bits of evidence.