title: Adding hard coded fixed line to d3 bar chart
body: <p>Hope you can help me with this, its almost an identical problem to (which does not appear to be complete, as no line shows):</p>
  
  <p><a href="https://stackoverflow.com/questions/13230979/d3-js-how-to-add-lines-to-a-bar-chart">d3.js How to add lines to a bar chart</a></p>
  
  <p>With the difference being I need to create a hard coded reference line for example at 7%. </p>
  
  <p>I've attempted to create the fiddle here, but cannot get the line to show.</p>
  
  <p><a href="http://jsfiddle.net/ComputerSaysNo/sstSe/1/" rel="nofollow noreferrer">http://jsfiddle.net/ComputerSaysNo/sstSe/1/</a></p>
  
  <p>I imagine it might be done by changing this...?</p>
  
  <p><code>bars.append("line")
      .attr("x1", 0)
      .attr("y1", function(d,i) { return height - d.average; })
      .attr("x2", 10)
      .attr("y2", function(d,i) { return height - d.average; });
  </code></p>
  
  <p>Many Thanks,</p>
  
  <p>Ryan.</p>