[
  {
    "mob": "minecraft:zombie",
    "persecond": 1.0,
    "attempts": 100,
    "amount": {
      "minimum": 30,
      "maximum": 90,
      "groupdistance": 10
    },
    "conditions": {
      "dimension": "minecraft:overworld",
      "norestrictions": true,
      "mindist": 15,
      "maxdist": 70,
      "minheight": 1,
      "maxheight": 256,
      "maxthis": 150
    }
  }
]