Al-Sa'ib bin Yazid (may Allah be pleased with him) said: I used to collect the tithe with Abdullah bin Utbah in the time of Sayyiduna Umar (may Allah be pleased with him), and he used to collect a twentieth from the trade goods of the dhimmis.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجزية / 18769