title: Power consumption of an iOS application
body: <p>I want check power usage of my iOS application.
  I tried with the Instruments.</p>
  
  <p>In the 'Energy Usage Level' it shows values 1/20 (0 to 20),indicating how much energy your app is using at any given time. </p>
  
  <p>What the value meant 0 to 20?.
  And how Can I export the value in to text document</p>
  
  <p><strong>Edit :</strong>  How can I convert it to percentage of energy usage ? </p>