       series: @values
       min: 'auto'
     })
+    @hoverDetail = new Rickshaw.Graph.HoverDetail({
+      graph: @chart
+      xFormatter: (year) -> "Year #{year}"
+      yFormatter: (numCranes) -> "#{Math.round(numCranes)} cranes"
+    })
   
   drawChart: ->
     @chart.render()

  numYears: 100
  runNumber: 0
  chart: null
  
  constructor: ->
    @values = []

    if firstZero > -1
      newVals = newVals[..firstZero]
    newData = newVals.map (v, i) => { x: @year+i, y: v }
    @values.push({
      name: "Run ##{@runNumber}"
      color: "rgba(0, 0, 0, 0.1)"
      data: newData})

  tick: =>
    @extendData()
