{
  "fields": [
    {
      "name": "postcode",
      "type": "string",
      "title": "Postcode"
    },
    {
      "name": "duty",
      "type": "integer",
      "title": "Duty"
    },
    {
      "name": "transactions",
      "type": "integer",
      "title": "Number of Transactions"
    }
  ],
  "missingValues": [
    ""
  ],
  "primaryKey": [
    "postcode"
  ]
}