At the beginning of YR3, Firm X paid $80,000 for a piece of property with 1,000 acres of timber. The firm estimated that a total of 30,000 trees could ultimately be removed from this site. They estimated that the land could be sold for $10,000 after completion of the project. During YR 3, Firm X spent $150,000 on labor to help with the cutting and treatment of the timber (intangible development cost). It also purchased a piece of equipment for $20,000 to help with the extraction (tangible development cost). The equipment had a 10year life and would be used for a different project after completing work on the current project. During YR 3, the firm extracted 10,000 trees, and sold 8,000 of these trees. At that time, the firm estimated that an additional 20,000 trees could still be extracted. In YR 4, Firm X spent an additional $12,000 to help extract more trees. Firm X extracted an additional 11,000 trees, and sold a total of 5,000 trees. At that time, the firm estimated that an additional 9,000 trees could still be extracted. Calculate the unit depletion rate for YR 3 and for YR 4.