Most CFM measurements are taken in an unobstructed test... like i said, look at the pitch of it, and you can make up a little math equation.
Take the RPM divide it by CFM and the higher the remaining number is a generalization of how much pressure it can generate without a real unit.
There is no real equation from just having those numbers but it can give you a general idea.
Edit: Don't let this equation 100% influence your desision... as my delta fan can push 250 CFM at 5000 RPM and it has a huge amount of static pressure... going by that equation compared to other fans it would have almost none.