Hello drpark,
Some information on this subject is coming. For a long time, we were uncertain just how much work was going to come from the ISB. The ISB assembles work units in 'batches' and it started out by assembling batches faster than we could crunch them. But guesses about how many batches there would be were just that - - guesses.

It is harder to keep track of individual work units, since server checks on returned results may indicate a need to issue more instances of a work unit for crunching. But we hope that the ISB will start issuing status updates soon that at least let us know how many batches have been returned to the ISB from the grids after crunching, how many are still on the grids being crunched and how many batches are still waiting at the ISB to be downloaded to the grids.

If you read http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=3206 you will see that the status was 60% - 72% complete. The large uncertainty was because almost 12% of the batches were on the grids (WCG and grid.org) being crunched.