Logical summation and graph

How do I get the overall profit for each month in a graph form for 7 the following case,

       Start date   M1   M2    M3   M4  

       5/2016       $5     $10   $15   $20

       7/2016       $2     $20   $35   $35

       6/2016       $7     $10   $12   $18

   I want a graph which shows:

  5/2016= $5

  6/2016=$17  ($7+$10)

  7/2016=$27  ($2+$10+$15)

  8/2016=$52  ($20+$12+$20)

  9/2016=$53  ($35+$18)

10/2016=$35