def _percent(x, total, default=0.0):
    if total:
        return 100.0 * x / total
    else:
        return default
Rotate minute store when new trading day data flowed in.
dataset/ETHPy150Open Yelp/mrjob/mrjob/tools/emr/audit_usage.py/_percent--crossover with--dataset/ETHPy150Open yinhm/datafeed/datafeed/datastore.py/Manager.rotate_minute_store