def perc_average(four_month_perc):
    """
    A function that computes the % change specific average. This is the total percent change over
    the four months

    :param:     four_month_perc     A series with the historical % change
    :return:    float               The total percent change over the four months
    """
    return ((((four_month_perc / 100) + 1).product() - 1) * 100)