Try a leakdown test - that will show you which cylinders are bleeding pressure, where.
But those comp numbers are very low - almost down to 'beyond serviceable limits'. If they don't come up with a wet test, then you've got some significant wear'n'tear in the old girl (lots of ring clearance, trashed head gasket, cracked pistons or burnt valves). If they come up, then it's tired rings - but don't expect 180's across the board, it sounds like that donk needs a refresh.