def METHOD_NAME(x, y):
    dataframe_util = pd.DataFrame({'x': x, 'y': y})
    if 0 in dataframe_util['y'].values:
        index_occurrence = dataframe_util['y'].idxmin(axis=0, skipna=True)
        utilization_perc = round(dataframe_util.loc[index_occurrence, 'x'], 1)
        utilization_days = int(utilization_perc * HOURS_IN_YEAR / (24 * 100))
        return str(utilization_perc) + '% or ' + str(utilization_days) + ' days a year'
    else:
        return 'all year'