title: Adding a Calculated Row in Tableau
body: <p>I am displaying a table in Tableau for toys sales , I want to introduce a calculated row based on the previous row data. How can I do this in Tableau.</p>
  
  <pre><code>Toys type   Sales in 2013   Sales in 2014
    type1        10                 15
    type2        20                 13
    type3        30                 28
    type4       X/30               X/28
  </code></pre>