curl --request GET \
  --url https://api.hubapi.com/marketing/v3/marketing-events/participations/{externalAccountId}/{externalEventId}/breakdown \
  --header 'Authorization: Bearer <token>'

{
  "results": [
    {
      "associations": {
        "contact": {
          "contactId": "<string>",
          "email": "<string>",
          "firstname": "<string>",
          "lastname": "<string>"
        },
        "marketingEvent": {
          "marketingEventId": "<string>",
          "name": "<string>",
          "externalAccountId": "<string>",
          "externalEventId": "<string>"
        }
      },
      "createdAt": "2023-11-07T05:31:56Z",
      "id": "<string>",
      "properties": {
        "attendanceState": "ATTENDED",
        "occurredAt": 123,
        "attendanceDurationSeconds": 123,
        "attendancePercentage": "<string>"
      }
    }
  ],
  "total": 123,
  "paging": {}
}