def METHOD_NAME():
    """load gapminder dataset's table only with non-former countries needed to complement the rest of sources."""
    ds = Dataset(DATASET_GAPMINDER_SYSTEMA_GLOBALIS)
    tb = ds["total_population_with_projections"]
    # reset index
    tb = tb.reset_index()
    # add source
    tb["source"] = SOURCE_NAME
    # filter countries
    msk = tb["geo"].isin(COMPLEMENT_COUNTRIES)
    tb = tb[msk]
    # rename countries
    tb["country"] = tb["geo"].map(COMPLEMENT_COUNTRIES)
    # columns
    tb = tb.rename(columns={"time": "year", "total_population_with_projections": "population"})
    # output columns
    tb = tb[["country", "year", "population", "source"]]
    # reset index
    tb = tb.reset_index(drop=True)
    return tb