title: Count of quarter between dates
body: <p>I want to calculate the count of total quarters (of a year) in the given time span.</p>
  
  <p>for example: </p>
  
  <pre><code>start date = 1-june -2009
  end date = 18-july-2011
  
  count should be = 10.
  
  one more 
  start date = 4-Jan-2009 
  end date = 27-oct -2010
  count =8.
  </code></pre>
  
  <p>I have not been able to get the correct result.</p>