The main region of 20 emitters experimentally observed until 2010 is above Z = 86: Fr, Ra, Ac, Th, Pa, U, Pu, and Cm. Only upper limits could be detected in the following cases: C decay of Ba, N decay of Ac, O decay of Th, Ne decays of Th and of U, Mg decays of U, Mg decay of Np, and Si decay of Pu and of Am.