  Through a detailed study of scaling near the magnetic field-tuned
superconductor-to-insulator transition in strongly disordered films, we find
that results for a variety of materials can be collapsed onto a single phase
diagram. The data display two clear branches, one with weak disorder and an
intervening metallic phase, the other with strong disorder. Along the strongly
disordered branch, the resistance at the critical point approaches $R_Q =
h/4e^2$ and the scaling of the resistance is consistent with quantum
percolation, and therefore with the predictions of the dirty boson model.
