The county librarian shall, on or before July 31 of each year, report to the board of supervisors and to the director of the Arizona state library, archives and public records on the condition of the county free library for the year ending on the preceding June 30. The report, in addition to other matters deemed expedient by the county librarian, shall contain statistical and other information deemed desirable by the director. For this purpose the director may send to the county librarians instructions or question blanks so as to obtain the material for a comparative study of library conditions in the state.