It is narrated from Nafi' (may Allah have mercy on him) that Abdullah bin Umar (may Allah be pleased with him) performed two Umrahs every year during the era of Abdullah bin Zubair (may Allah be pleased with him).
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 777
Hadith Takhrijاسناده صحيح أخرجه البيهقي : 3444 ۔ وفي المعرفة السنن والآثار له (2701)۔