<c3 width=100% height=400px>

  data: {
  	x: 'x',
      columns: [
      ['x',1972,1992,1996,2000,2004,2008,2012,2016],
      ['K1-women',22,26,30,20,19,21,21,21],
      ['C1-men',22,31,30,16,16,16,17,19],
      ['C2-men',19,17,15,12,12,12,14,19],
      ['K1-men',37,44,44,23,25,21,22,21]

      ],
       types: {
           K1-women: 'area',
           C1-men: 'area',
           C2-men: 'area',
           K1-men: 'area',
      },
       groups: [['K1-women','C1-men','C2-men','K1-men']],
       axis: {
       x: {
           type: 'category',
          categories: ['1972','1992','1996','2000','2004','2008','2012','2016',]
      }
  }
  }

</c3>

<c3 width=100% height=400px>

  data: {
  	x: 'x',
      columns: [
      ['x'],

      ],
       types: {
      },
       groups: []],
       axis: {
       x: {
           type: 'category',
          categories: []
      }
  }
  }

</c3>