N.M. Stat. § 4-3A-11
Upon the effective date of this act, the treasurer of Valencia county shall ascertain the amount of unexpended funds and securities in the treasury of Valencia county and shall also ascertain the amount of unpaid obligations and expenses of Valencia county government which will be required to be paid between the effective date of this act and the end of the sixty-ninth fiscal year. The excess of such unexpended funds and securities over such obligations and Valencia county government expenses shall be divided and paid by the treasurer of Valencia county to Cibola and Valencia counties in the proportion that the assessed valuation of all property in each county, as of January 1, 1981 bears to the total assessed valuation of all property in both counties as of January 1, 1981.
NMS § 4-3A-11