def durationBucket(durationStr):
    """
    Return string category label for call duration
    """
    duration = int(float(durationStr))
    if duration < 60:
        return "0 to 1 min"
    elif duration < 120:
        return "1 min to 2 min"
    elif duration < 180:
        return "2 min to 3 min"
    elif duration < 300:
        return "3 min to 5 min"
    elif duration < 600:
        return "5 min to 10 min"
    else:
        return "over 10 min"