Here are the results from the toilet bowl flushing experiment

Semester
Clockwise
Counterclockwise
Fall 2012
45
36
Fall 2011
63
64
Spring 2011
31
31

As several of you pointed out, the water can spin in either direction.  The Coriolis force does not play a role.  The direction of the spin is determined by the design and shape of the toilet itself.