title: How do I get a proportion of each row?
body: <p>I have a large dataset over 10 000 records.
  The data looks like this</p>
  <pre><code>Id  Ap   Ak    Al   Aj
  602 1    0     1    1
  603 0    1     1    1
  603 1    1     1    0
  </code></pre>
  <p>Some of the Ids appear more than once. How do I to get the proportion for each row?
  I have tried : <code>prop.table(table(rep$id), margin = 1)* 100</code>, this just returns 1s under each id.</p>