5% was pretty standard for most societies pre industrial revolution though. Only ruler class knew literacy.The overwhelming majority of Somalis are nomads. Nomads are illiterate. They don't know how to read or write. Nomadic societies are generally oral based and don't have a literate tradition. The majority of Somalis only learned how to read and write very recently. In 1972, only 5% of the population was literate until Said Barres mass literacy campaign, which was a remarkable success.
I'm talking about why the ruling class didn't write their books in Somali.