title: Group data by week but display date format axis
body: <p>I have data which I want to display on an Excel column chart. It represents the number of sales per week, where the date is the first day of the week:</p>
  
  <p><img src="https://i.stack.imgur.com/vvSay.png" alt="enter image description here"></p>
  
  <p>If I leave the dates as dates then Excel interprets this as data for one day out of seven, so I get thin columns with large gaps:</p>
  
  <p><img src="https://i.stack.imgur.com/7bLEr.png" alt="enter image description here"></p>
  
  <p>I can resolve this by formatting the dates as text, which gives me the style I want:</p>
  
  <p><img src="https://i.stack.imgur.com/f8qIU.png" alt="enter image description here"></p>
  
  <p>However, I want a date scale where only the first of each month is labelled, which I think requires a date formatted axis.</p>
  
  <p>Basically, I want to achieve this in Excel instead of paint:</p>
  
  <p><img src="https://i.stack.imgur.com/Ds6pP.png" alt="enter image description here"></p>
  
  <p>Any ideas on how (if) this can be done?</p>