y   x1    x2
   61  21.0  57.0
   87  28.3  41.5
   98  27.5  58.0
  104  26.8  36.5
  102  28.3  40.0
   63  30.5  34.0
   27  30.8  37.0
   14  33.6  20.0
   30  31.3  21.0
   67  33.0  24.5
    6  34.3   6.0
   18  33.0  21.0
   42  32.0  28.0
   60  27.8  39.0
   82  25.0  41.0
   77  26.0  51.0
  108  18.0  70.0
   77  24.8  48.0
   93  26.0  56.0
  100  27.1  31.0
  118  29.0  41.0
   74  34.0  25.0
   43  28.3  13.0
   19  31.0  19.0
   23  31.8  17.0
   25  33.5  18.5
   40  34.5  16.0
   21  34.3  26.0
   23  26.5  26.0
   56  27.3  24.5
   59  25.8  29.0
   89  18.5  53.5
  102  19.0  48.0
   97  16.3  79.5