Comparison between the MDF derived in this work (grey shaded histogram) and those predicted from the chemical evolution models by M17 and its revised version presented here. The MDF from the original models is presented as the empty curves, while the coloured shaded curves show the same distributions after removal of 75% (M17 model) and 50% (new model) of the metal-poor stars ([Fe/H] < −0.6). The distributions are normalised to have a unit area.