def share_of_shelf_index(products_of_brand_x, total_products):
    """Return share of shelf index showing the percentage of total products made up by brand X.

    Args:
        products_of_brand_x (int): Number of products of brand X in portfolio, category, or on shelf.
        total_products (int): Total number of products of all brands in portfolio, category, or on shelf.

    Returns:
        Percentage of shelf, category, or portfolio made up by brand X
    """

    return (products_of_brand_x / total_products) * 100