curl --request GET \
  --url https://external-api.kalshi.com/trade-api/v2/series/{series_ticker}/events/{ticker}/forecast_percentile_history \
  --header 'KALSHI-ACCESS-KEY: <api-key>' \
  --header 'KALSHI-ACCESS-SIGNATURE: <api-key>' \
  --header 'KALSHI-ACCESS-TIMESTAMP: <api-key>'

{
  "forecast_history": [
    {
      "event_ticker": "<string>",
      "end_period_ts": 123,
      "period_interval": 123,
      "percentile_points": [
        {
          "percentile": 123,
          "raw_numerical_forecast": 123,
          "numerical_forecast": 123,
          "formatted_forecast": "<string>"
        }
      ]
    }
  ]
}