We are not economists, so no, we have not analyzed what the drag might be. We can determine, though, that an order of magnitude of $10 billion to $15 billion would be needed to carry us through recessions similar to the ones that have occurred in the past, analyzing the variability in unemployment rates.
The $2 billion, as it stands now, does nothing to stabilize premium rates, because it must be rebuilt each year. You could have a zero in there and you'd have the same net effect. It doesn't really matter.