How do I translate millisecond graphs found in VIC to percent?

The formula is:
x/200
...where x is the number of ms reported. This because the sampling interval of the millisecond values presented is defaulting to 20 seconds.

This should be

x / 200 / <Num of cores>

The summation for the VM in the graphs is all the cores added together. So if you want the average for the VM as a whole you need to divide by the number of cores allocate to the VM.