(1) The commission shall keep on file all examination papers and their markings and all other papers, documents and communications received by it. All such reports and files of the commission shall be public records and accessible at convenient times in like manner as other public records.
(2) The commission may destroy any reports and files of the commission which are:
(a) Not less than four years old.
(b) Less than four years old, provided they have been recorded by means of photography, microphotography, photocopying or filming and the commission determines that they have no further evidential value.