Two Dimensions for x and y (Two graphs in one)

[#1]

Hi,

I am trying to make a graph of capability against demand. I have 3 columns: Demand (date), Coming available (end date) and Role.

I want to present on one graph the cumulative demand, the cumulative coming available and to be able to sort it by role.

In other words, I want to have a graph with the X axis of dates and Y axis of number available/demand (for each role should be two curves).

Example:

Role	Demand
Developer	10/6/2016
PM	15/6/2016
Developer	20/7/2016

Role	Coming available
PM	10/7/2016
Developer	15/6/2016
...	...

I hope it was clear! Thanks in advance