326(1)The insurer shall form a reserve fund to consist of all money that remains on hand at the end of each year after payment of expenses and losses; and in addition shall levy an annual assessment, not exceeding twenty-five per cent, and not less than five per cent, on the premium notes held by the insurer until such reserve reaches the sum of five hundred dollars for every one hundred thousand dollars of the first one million dollars insurance in force, and three thousand dollars for each additional one million dollars or part thereof in force, up to which minimum level it shall be maintained.