  We report a systematic study of the contact resistance present at the
interface between a metal (Ti) and graphene layers of different, known
thickness. By comparing devices fabricated on 11 graphene flakes we demonstrate
that the contact resistance is quantitatively the same for single-, bi-, and
tri-layer graphene ($\sim800 \pm 200 \Omega \mu m$), and is in all cases
independent of gate voltage and temperature. We argue that the observed
behavior is due to charge transfer from the metal, causing the Fermi level in
the graphene region under the contacts to shift far away from the charge
neutrality point.
