content: {
    "$defs": {
      "Percentage": {
        "description": "Similar to an Amount, but designed for percentages and includes % symbol in JSON output.",
        "pattern": "^\\-?[0-9]+(\\.[0-9]+)?%$",
        "title": "Percentage",
        "type": "string"
      }
    },
    "$id": "https://gobl.org/draft-0/num/percentage",
    "$ref": "#/$defs/Percentage",
    "$schema": "https://json-schema.org/draft/2020-12/schema"
  }