We're currently in the process of analyzing a large dataset which gives us up to 10 past addressess for around 330 million individuals.
This will give us estimates of moves per year that we hope will be more accurate that the TargetSmart equivalent, since Equifax has better tracking of address history for nonvoters and those unlikely to be in the voter file.
At the moment, we have confidence in our numbers down to a county level. With more work, we'll be able to provide these numbers at the congressional district and state legislative district level.