title: Calculating Yearly Average by current month
body: <p>I need to create a SS that calculates the yearly average from January until the end of the previous month.</p>
  <p><a href="https://i.stack.imgur.com/66SPB.jpg" rel="nofollow noreferrer">Excel Example</a></p>
  <p><img src="https://i.stack.imgur.com/66SPB.jpg" alt="" /></p>
  <p>Currently I have =SUM(A2:G2)/12 and each month I go in an change the range, but  I would like it to update each month to include the month that just finished.</p>
  <p>Any help would be appreciated.</p>