What percentage of the 1st century Christian population served as authorized tradents of the oral tradition?

Some of those who subscribe to the theory that the Jesus traditions were not published until decades after the resurrection assert that authorized tradents were responsible for accurately preserving the traditions via "oral tradition" methods. For example, Richard Bauckham contends that > Of crucial importance for our whole argument in this book is the role of individual authors and tradents of Jesus traditions. We have suggested that the traditions were originated and formulated by named eyewitnesses, in whose name they were transmitted and who remained the living and active guarantors of the traditions. **In local Christian communities which did not include eyewitnesses among their members, there would probably be recognized teachers who functioned as authorized tradents of the traditions they had received from the eyewitnesses either directly or through very few (authorized) intermediaries.**1 Which leads to the question: What percentage of the 1st century Christian population is assumed to have served as (Bauckham-style) authorized tradents of the oral tradition, who would have accurately memorized something comparable to what would one day be contained in Matthew's Gospel? [Reference to a published estimate would be most appreciated.] Ultimately, am trying to establish whether this is a greater percentage than those who were literate (at least able to read) within the early Christian population. ___ 1 Richard Bauckham, Jesus and the Eyewitnesses: The Gospels as Eyewitness Testimony, 2nd ed. (Grand Rapids, MI: Eerdmans, 2017), 290.