title: Add column with number of observations to esttab summary statistics table
body: <p>I would like to make a summary statistics table using <code>esttab</code> from the <code>estout</code> package on SSC. I can make the table just fine, but I would like to add a column that counts the number of non-missing observations for each variable. That is, some variables may not be complete and I would like this to be clear to the reader.</p>
  
  <p>In the example below I removed the first five observations for <code>price</code>, so I would like a 69 in that row. But my code doesn't include row-specific observation counts, only the total number of observations in the footer.</p>
  
  <pre><code>sysuse auto, clear
  estpost summarize, detail
  replace price = . in 1/5
  local screen ///
      cells("N mean sd min p50 max") ///
      nonumber label 
  esttab, `screen'
  </code></pre>
  
  <p>This yields an empty <code>N</code> column, which I would prefer to have at 69 , followed by all 74s.</p>