title: SSRS report Row grouping and average value for each group
body: <p>I have a report with a row grouping in a table. Now I want to add an avarage value for each group. E.g. there's a table with data on employees visiting an office:
  <code></p>
  
  <p>Name  |  In                        |  Out</p>
  
  <p>John  |  2012-10-30 04:49:35.000   |   2012-10-30 05:49:35.000<br>
  Mark  |  2012-10-30 04:69:35.000   |   2012-10-30 04:79:35.000<br>
  John  |  2012-12-15 04:49:35.000   |   2012-10-30 04:49:35.000  </p>
  
  <p></code></p>
  
  <p>I've made a grouping in my report on Name and get amount of visits for each employee:</p>
  
  <p><code>
  Name  |   Visits<br>
  John  |   2<br>
  Mark  |   1
  </code></p>
  
  <p>Now a need to add a column with an avarege time each employee spent in the office.</p>
  
  <p>is it possible?</p>