TABLE 1

Sample Size and Years of Observation by Region in Ascending Order of Years of Follow-up

RegionSample SizeBirth YearsFollow-up YearsYears of Follow-up
Texas26631996–20031996–20049
Utah5561995–20031995–200410
Arkansas3621993–20021993–200311
Oklahoma5461994–20031994–200411
Colorado9721989–20031989–200416
North Carolina16281989–1993, 1995–20031989–200416
California46861983–20021983–200320
Iowa8491983–20031983–200422
New York33551983–20031983–200422
Georgia8891983–20031983–200422