Smog pump plots are available at the OEMs, but I haven't got one.
Pressure output must exceed maximum exhaust backpressures, though, so I'd expect they can develop 10 - 12 psi at the very least.
I can recall that one such common pump at Ford drew about a horsepower at rated rpm, normal maximum rpm. Either the little buggers are enormously inefficient, or they have a pretty significant flow rate. Considering what exhaust flow rates are, that's not so surprising.