The sputtering yield of polycrystalline monatomic solids at normal incidence show a universal behaviour for light and heavy ions in the threshold regime. For heavy ions at higher energies a similar behaviour has been explained, based on first principles. In this work a relation is derived valid for both of these energy regimes. The relation is based on reasonable assumptions for the momentum distribution of the recoil target atoms and on the usual emission condition (planar surface potential). A "surface correction" — important for light ion sputtering — is also introduced. It is shown that experimental data for light ion sputtering at higher energy are also in good agreement with this relation.