For purposes of this subchapter, the term "high poverty area" means an urban census tract, a contiguous group of urban census tracts, a block number area in a nonmetropolitan county, a contiguous group of block number areas in a nonmetropolitan county, or an Indian reservation (as defined in section 3202(9) of title 25), with a poverty rate of 20 percent or more among individuals who have not attained the age of 22, as determined by the Bureau of the Census.