The board shall set aside five per centum of all premiums collected for the creation of a surplus until this surplus shall amount to one hundred thousand dollars ($100,000), and thereafter they may set apart such percentage, not exceeding five per centum, as in their discretion they may determine to be necessary to maintain such surplus sufficiently large to cover the catastrophe hazard of all the subscribers to the fund and to guarantee the solvency of the fund.
77 P.S. § 2609