title: XSLT 2.0: Calculate age from DOB
body: <p>Is there a function to calculate a duration from 2 dates within XSLT 2.0?</p>
  
  <p>I'm trying to calculate the following from a Date Of Birth and Current Date:</p>
  
  <ul>
  <li>Age in years</li>
  <li>Age in months</li>
  </ul>