def write_growth_rates_file(growth_rates, growth_rates_filename):
    """ Write a growth rates data frame to a file.

    Parameters
    ----------
    growth_rates : pandas.DataFrame
        Growth rates information
    growth_rates_filename : str
        Path to file for storing growth rates data frame in CSV format
    """
    growth_rates.to_csv(growth_rates_filename, index=False)
    return
