Graphite conductivity?

In chem (high school chem, that is), we are taught that the structure of graphite is pretty much a bunch of sheets of carbon with free electrons in between the sheets.
This sructure explains why graphite conducts electricity and why it it is ‘greasy’.
If graphite does have this two dimensional structure, then does the conductivity of graphite differ with respect to the direction of the current? (parallel or perpendicular to sheets)

Electrical Conductivity

The conductivity of silicon also depends on the direction of current through the lattice.