Line graph needed to forecast 2018 savings

Hi,

Referring to the Data Worksheet attached
I need to generate a line graph that shows 3 sets of data for expected savings to be achieved in year 2018.

Carryover savings (from 2017)
Realised saving 2018
Carryover savings + Realised Savings

The savings are based on a 12 month period. If savings begun to be realised on 1st July 2017, then 50% would be realised in 2017 and the other 50% in 2018.

Graph range is 'year 2018' in monthly increments (x axis) and Y axis is Savings value in Euros
Graph Line 1 = the sum of column AN (358742) is to be plotted for each month
Graph Line 2 = Column AQ but each month it accumulates
Example
in Jan 2018 there is no savings.
in Feb 2018 there will be 4575 savings
in Mar 2018 there will be 4611 savings + 4575 savings from Feb = 9186
in Apr 2018 there will be 8288 savings + 9186 from Feb/mar =17474
in May 2018 there will be 8390 savings + 17474
etc etc until Dec 2018

Graph Line 3 = the sum of line 1 + line 2 for each month ie Feb would equal 358742 +4575, march would equal 358742 + 9186 and so on.

thanks for your help.