The population partition of metastable atoms after ion beam sputtering of polycrystalline Ni was studied. Resonant multiphoton ionization using double resonant two-color two-step photoionization was used. This allows the quantitative measurement of the relative population of all metastable states. The high lying metastable states with excitation energies around 2 eV show populations of the order of 10% of the ground state population which is several orders of magnitude higher than expected. The anomalous population partition is interpreted in the resonant electron tunneling model.