(1) Matters to be considered. In determining percentages of permanent disabilities, account shall be taken of the nature of the physical disablement, the disfigurement if of a kind likely to limit the employee in procuring or holding employment, the cumulative effect of multiple injuries, the occupation of the employee, and his age at the time of accident causing the injury, or manifestation of the occupational disease, consideration being given to the diminished ability of the afflicted employee to compete in an open labor market within a reasonable geographical area considering all the personal and economic circumstances of the employee, and other factors as the commission may deem relevant, provided that when a scheduled or unscheduled income benefit is paid or payable for the permanent partial or total loss or loss of use of a member or organ of the body no additional benefit shall be payable for disfigurement.
(2)  Preparation of schedules — Availability for inspection — Prima facie evidence. The commission may prepare, adopt and from time to time amend a schedule for the determination of the percentages of unscheduled permanent injuries less than total, including, but not limited to, a schedule for partial loss of binaural hearing and for loss of teeth, and methods for determination thereof. Such schedule shall be available for public inspection, and without formal introduction in evidence shall be prima facie evidence of the percentages of permanent disabilities to be attributed to the injuries or diseases covered by such schedule.