title: Google Sheets formula to track number of event occurrence in the last 4 weeks
body: <p>At work we are tracking a certain event that is suposed to occur once a week for each of our customers. A sample of the sheet we use to track this can be seen here:</p>
  
  <p><a href="https://docs.google.com/spreadsheets/d/128JhxL1gv2vTF027zkjYDGp48MIQ5-q9F9B6bIltCfM/edit#gid=0" rel="nofollow noreferrer">https://docs.google.com/spreadsheets/d/128JhxL1gv2vTF027zkjYDGp48MIQ5-q9F9B6bIltCfM/edit#gid=0</a></p>
  
  <p>I'm trying to create an index that counts how many events occurred in the last 4 weeks for each customer (i.e cells that contain "OK") but I'd like it to be updated as  the weeks go by without me having to change the range in the formula every week. Any ideas? Thanks!</p>
  
  <p>Edit: the event we are tracking is related to the COVID context so we can't be sure for how many weeks we'll keep tracking it. There are 8 weeks in the sample, but we may add ore over time</p>