We devise a method for the disc/halo mass decomposition of the rotation curves of spiral galaxies that was outlined by us in a previous paper. Upon application to a larger sample of 58 spirals, we confirm our earlier results. In particular, we find that the disc-to-halo mass ratio at the optical radius, M_disc_/M_halo_, is a strong function of luminosity, M_disc_/M_halo_ is proportional to L^2/3^_B_.