(12) Assistance for rural providers furnishing services in low population density areas (A) In general In the case of ground ambulance services furnished on or after July 1, 2004 , and before January 1, 2023 , for which the transportation originates in a qualified rural area (identified under subparagraph (B)(iii)), the Secretary shall provide for a percent increase in the base rate of the fee schedule for a trip established under this subsection. In establishing such percent increase, the Secretary shall estimate the average cost per trip for such services (not taking into account mileage) in the lowest quartile as compared to the average cost per trip for such services (not taking into account mileage) in the highest quartile of all rural county populations. (B) Identification of qualified rural areas (i) Determination of population density in area Based upon data from the United States decennial census for the year 2000, the Secretary shall determine, for each rural area, the population density for that area. (ii) Ranking of areas The Secretary shall rank each such area based on such population density. (iii) Identification of qualified rural areas The Secretary shall identify those areas (in subparagraph (A) referred to as “qualified rural areas”) with the lowest population densities that represent, if each such area were weighted by the population of such area (as used in computing such population densities), an aggregate total of 25 percent of the total of the population of all such areas. (iv) Rural area For purposes of this paragraph, the term “rural area” has the meaning given such term in section 1395ww(d)(2)(D) of this title . If feasible, the Secretary shall treat a rural census tract of a metropolitan statistical area (as determined under the most recent modification of the Goldsmith Modification, originally published in the Federal Register on February 27, 1992 ( 57 Fed. Reg. 6725 ) as a rural area for purposes of this paragraph. (v) Judicial review There shall be no administrative or judicial review under section 1395ff , 1395oo of this title , or otherwise, respecting the identification of an area under this subparagraph.