To get asymetric ionisation (H+ H-) is around four times as much.
The electron (H-) one gets for free if metal is present....And as said Rydberg matter does it at no cost. The Wiki source is based on an other process. H+ needs the well known 13,6 eV and then the electron is free to join H what gives a small contribution. See Mills GUTCP. So the real factor is about 3 without any help - But all LEC have a Rydberg matter structure surface.