The scaling of conductance across metal-molecule-metal junctions consisting of self-assembled monolayers of dithiol molecular wire candidates is demonstrated through current-voltage measurements carried out by two experimental techniques. We show that scanning tunneling microscopy measurements on single molecules are correlated with crossed-wire measurements of similar to10(3) molecules. This implies that the conductance through a group of parallel molecules is a linear superposition of the individual molecular conductance. Our results also indicate that intermolecular charge hopping does not strongly contribute to charge transport in a self-assembled monolayer, an important factor for the design of future molecular-based devices.