Example:  distance travelled by transportation type

With the sample data below, how does one achieve a common category for the transportation type such that the bars for each series are side by side and commonly labelled.

Series 1:

Ndatapoint(10, "Car")
Ndatapoint(20, "Bus")
Ndatapoint(40, "Plane")

Series 2:

Ndatapoint(30, "Car")
Ndatapoint(30, "Bus")
Ndatapoint(50, "Plane")