Some of the people in the top ranks are real surprises.
Top 100 actors by Avg Box Office Gross of all movies
Top 100 actresses by Avg Box Office Gross of all movies
When you said “some surprises!” I had a feeling Orlando Bloom would be up there. He’s been lucky. He’s not a bankable star like Ford (whose movies have grossed more than $3 billion), but he started his career by getting into a huge hit franchise - LOTR - and then was cast as a romantic, secondary lead in The Johnny Depp Show. I mean, Pirates of the Carribean. Which has turned into an enormous hit and a franchise. Put him on his own, and what do you get? Troy. I mean, everybody has some flops, but I don’t think he can carry a big-budget movie on his own. It’d be interesting if it was possible for this thing to factor in costs. Troy made $133 million at the U.S. box office, which sounds impressive… until you learn that it cost $185 million to make, so it didn’t even come close to making a profit here. Maybe it made one worldwide, but it wasn’t a big hit.
A lot of these actors are just there because of parts in huge hits, not because they’re major stars. Sorted by average gross, Billy Dee Williams is #2. I rest my case.
Even though Samuel L. Jackson is ranked #1 for Total Gross for All Movies (even ahead of Harrison Ford), his average drops him down to 37 (just behind Cuba Gooding Jr.).
For # of films w/grosses over $100M, Tom Hanks is in first with 14, followed by Tom Cruise with 12. For average gross, their ranks are 10 & 11 respectively.
Just wait until Elizabethtown opens. That’ll drop Bloom fast. 
Actually, why is Bloom only “starring” in 4 of his total 8 films. Which are they counting and not counting (I’m guessing LOTR is out, but that doesn’t really make sense). 
For their sakes (all of the so-called less-than-bankable stars), I hope they got a cut of the gross.
So why aren’t we seeing more movies starring Bonnie Hunt and Carrie Fisher, with Julie Andrews in a supporting role? Now there’s a money making combination!