Musnad Ahmad 25:197

Ibn Numayr narrated to us, al-‘Ala’ ibn Salih narrated to us, al-Minhal ibn ‘Amr narrated to us, from Sa‘id ibn Jubayr, that a man came to Ibn ‘Abbas and said: "Ten [surahs] were revealed to the Prophet, may Allah bless him and grant him peace, in Makkah, and ten in Madinah." He said: "Who says that? There were revealed to him in Makkah fifteen, and in Madinah ten, sixty-five and more."