What is the earliest mention of Draco’s birthday?

Both harrypotter.fandom.com and hp-lexicon.org list 1980 June 5th as his birthday. A JKR tweet does confirm this, but as it was a reply to another user, it seems as though this was already known. Where was the date published prior to 2015?

I don’t believe the exact date is ever mentioned in any of the books, though upper and lower bounds could be established based on what year he is in and when he is eligible for apparition tests and such.

Any thoughts?