title: conditional counting from a CSV
body: <p>I have a CSV of titanic data, with several different columns describing the passengers. </p>
  
  <p>I want to find the percentage of passengers who both survived and where adults. </p>
  
  <p>If you look at the data I have included, you will have a much better picture of what I'm talking about. I can't seem to find anything matching my exact situation online. Any help would be appreciated.</p>
  
  <p>This is the data:</p>
  
  <pre><code>     Class    Sex    Age  Survived
  1      1st   Male  Child       Yes
  2      1st   Male  Child       Yes
  3      1st   Male  Child       Yes
  4      1st   Male  Child       Yes
  5      1st   Male  Child       Yes
  6      1st   Male  Adult        No
  7      1st   Male  Adult        No
  8      1st   Male  Adult        No
  9      1st   Male  Adult        No
  10     1st   Male  Adult        No
  11     1st   Male  Adult        No
  12     1st   Male  Adult        No
  13     1st   Male  Adult        No
  14     1st   Male  Adult        No
  15     1st   Male  Adult        No
  16     1st   Male  Adult        No
  </code></pre>