title: how to get historic head count for company based on start and end dates
body: <p>HR gave me a very basic <code>.xlsx</code> file:</p>
  
  <pre><code>name   startdate   enddate
  jdoe   4/30/2005  
  kdoe   11/1/2005   3/11/05
  </code></pre>
  
  <p>Not everyone has a end date.</p>
  
  <p>What they want is a list of per week or per day (not sure yet) historically what the head count of the company was/is</p>
  
  <p>I've tried a pivot table and it will give me how many people joined or left during a month or year but not a cumulative total also I don't know how to add one and subtract the other.</p>
  
  <p>Any ideas on a formula would be great.</p>