etymology - What is the proper pronunciation for 十分/１０分? じっぷん or じゅっぷん?

My Japanese textbook only lists じゅっぷん. Our Japanese sensei (a quite old woman) says じっぷん but notes that it's optionally じゅっぷん. Our TAs all say じゅっぷん.

I understand that Middle Chinese 十 was "jip" and the thing went through じふ->じう->じゆう->じゅう, but what about 十分?

Clearly じっぷん seems to be the etymologically correct pronunciation, but which one is the more modern-day official and widespread pronunciation (i.e. more commonly used and accepted), rather than simply historically correct?

Edit: How about １０分? Is the more common pronunciation of １０分 different?

Answer

I guess we can put it to a vote.

Technically, じっぷん seems to be the correct choice. Posts on this page say that in a 漢和辞典 じっ is listed as a reading of 十, but じゅっ isn't. Moreover, the page claims that about half of the TV announcers (for baseball) do take care to pronounce it じっ.

I don't have a TV, so I don't have an opinion on that, but in daily life, I think I hear じゅっぷん almost exclusively.