Deluge. Count number of instances in list (or map)

Deluge. Count number of instances in list (or map)

Example:
Have put the following in a list:

Name      Department
John        A
Dave       C
Mary        A
Jane        C
Pete         B
Oscar      A

Want to list the count for each Department (and put it into a list or map)
like:
Department Count
A                  3
B                  1
C                  2

Have tried with combinations of Count() and Size() and distinct(), but not find a way around this.
Great if someone have examples.


Thanks,
Larry