title: Angular2 how to do highchart tootip formatter - Additional value
body: <p>In Series I have used </p>
  
  <pre><code>series: [
          {
            name: 'High usage',
            data: highUsage,
            color: '#009DDB'
          },
          {
            name: 'Normal usage',
            data: normalUsage,
            color: '#83C580'
          }
  ]
  </code></pre>
  
  <p>In tooltip </p>
  
  <pre><code>tooltip: { 
      crosshairs: [true, true], 
      formatter: function() { 
  
      }
  }
  </code></pre>
  
  <p>My JSON format is </p>
  
  <pre><code>"data": {
      "low_usage": [
        {
          "percentage": 77.9,
          "machine": 3
        },
        {
          "percentage": 22.8,
          "machine": 1
        }
      ],
  </code></pre>
  
  <p>here everything working fine, but I need to show the number of machines also in tooltip like <b>Percentage: 100% (3 machines)</b><br/>
  What I have to do in the formatter.</p>
  
  <pre><code>{
  "data":{
    "normal_usage":[  
       {  
          "machine":1,
          "percentage":4.3
       },
       {  
          "machine":0,
          "percentage":0
       }
    ],
    "high_usage":[  
       {  
          "machine":0,
          "percentage":0
       },
       {  
          "machine":0,
          "percentage":0
       }
    ]
  },
  "error_path":"no error",
  "success":true
  }
  </code></pre>
  
  <p>This is my input format I send the data based on high usage and low usage</p>