title: Percentage of similarity between two colulmns
body: <p>Lets say I have two columns:</p>
  
  <pre><code>A  B
  1  1
  2  2
  3  4
  4  4
  5  4
  6  6
  </code></pre>
  
  <p>Is there a way to calculate the percentage of similarity, so that in example above we find that columns A and B are 67% the same. </p>