def national_insurance_contribution(pre_tax_income):
    """
    Returns the total amount of national insurance contributions for the year.
    You pay National Insurance contributions if you earn more than £200 a week.
    You pay 12% of your earnings above this limit and up to £800 a week.
    The rate drops to 2% of your earnings over £801 a week.
    :param pre_tax_income: The yearly income before tax.
    :return: The national insurance contribution.
    """
    weekly_income = pre_tax_income / 52

    if weekly_income <= 200:
        return 0

    if weekly_income <= 800:
        return ((weekly_income - 200) * 0.12) * 52

    return (600 * 0.12 + (weekly_income - 800) * 0.02) * 52