code: def get_throttled_by_provisioned_read_event_percent(
          table_name, lookback_window_start=15, lookback_period=5):
      
      try:
          metrics = __get_aws_metric(
              table_name,
              lookback_window_start,
              lookback_period,
              'ReadThrottleEvents')
      except BotoServerError:
          raise
  
      if metrics:
          lookback_seconds = lookback_period * 60
          throttled_read_events = (
              float(metrics[0]['Sum']) / float(lookback_seconds))
      else:
          throttled_read_events = 0
  
      try:
          table_read_units = dynamodb.get_provisioned_table_read_units(
              table_name)
  
          throttled_by_provisioned_read_percent = (
              float(throttled_read_events) /
              float(table_read_units) * 100)
      except JSONResponseError:
          raise
  
      logger.info('{0} - Throttled read percent by provision: {1:.2f}%'.format(
          table_name, throttled_by_provisioned_read_percent))
      return throttled_by_provisioned_read_percent
docs: Returns the number of throttled read events in percent
  
      :type table_name: str
      :param table_name: Name of the DynamoDB table
      :type lookback_window_start: int
      :param lookback_window_start: Relative start time for the CloudWatch metric
      :type lookback_period: int
      :param lookback_period: Number of minutes to look at
      :returns: float -- Percent of throttled read events by provisioning