0 - 10:  2   2
  11 - 20:  2   4
  21 - 30:  3   7
  31 - 40: 11  18
  41 - 50: 12  30
  51 - 60: 22  52
  61 - 70: 26  78
  71 - 80: 27 105
  81 - 90: 16 121
 91 - 100:  9 130

average:  64.27