text:'<span class="chart_title">Number of requests</span>',
    useHTML: true,
    widthAdjust:-20
  },
  xAxis:{
    tickmarkPlacement:'on',
    tickInterval: tickInterval,
    categories:numberOfRequestsData.names,
    labels:{ enabled:false }
  },
  yAxis:{
    min:0,
    reversedStacks: false
  },
  plotOptions:{
    series:{
      stacking:'normal',
      groupPadding:0,
      pointPlacement:'on',
      shadow: true
    }
  },
  legend: {
      borderWidth: 0,
      itemStyle: { fontWeight: "normal" },