Sec. 12. (a) Dependents under this chapter shall consist of the following three (3) classes:
(1) Presumptive dependents.
(2) Total dependents in fact.
(3) Partial dependents in fact.
(b) Presumptive dependents shall be entitled to compensation to the complete exclusion of total dependents in fact and partial dependents in fact and shall be entitled to such compensation in equal shares.
(c) Total dependents in fact shall be entitled to compensation to the complete exclusion of partial dependents in fact and shall be entitled to such compensation, if more than one (1) such dependent exists, in equal shares. The question of total dependency shall be determined as of the time of death.
(d) Partial dependents in fact shall not be entitled to any compensation if any other class of dependents exist. The weekly compensation to persons partially dependent in fact shall be in the same proportion to the weekly compensation of persons wholly dependent as the average amount contributed weekly by the deceased to such partial dependent in fact bears to his average weekly wages at the time of the disablement. The question of partial dependency in fact shall be determined as of the time of the disablement.