Each corporation organized under sections 44-3312 and 44-3313 shall annually on March 1 file with the department its statement for the preceding calendar year, and in the form prescribed by the director, showing all premiums received by it for the issuance of legal expense insurance in this state. Such annual statements may use accounting principles common to its business, but such accounting principles must enable the director to ascertain whether the reserve required by section 44-3317 has been maintained.