Complex sentence: Among Jews, 68% were Sabras, mostly second-or third-generation Israelis, and the rest are olim (Jewish immigrants to Israel)--22% from Europe and the Americas, and 10% from Asia and Africa, including the Arab countries.
Split into simpler sentences: Among Jews, 68% were Sabras, mostly second-or third-generation Israelis, and the rest are olim. Of the olim, 22% are from Europe and the Americas, and 10% from Asia, Africa, and Arab countries.