TABLE 1.

Characteristics of Each Subgroup (With 95% Confidence Intervals)

Subgroup	Subgroup 1	Subgroup 2	Subgroup 3	Subgroup 4
Size	120	197	212	4316
Average ICD-9 codes	150.0 (131.1–168.9)	178.6 (158.0–199.3)	103.6 (94.5–112.6)	20.8 (19.9–21.6)
Proportion of boys	0.6 (0.5–0.7)	0.7 (0.6–0.8)	0.8 (0.8–0.9)	0.8 (0.8–0.8)
Mean age of diagnosis in years	9.5 (8.8–10.1)	7.7 (7.1–8.3)	7.6 (7.1–8.0)	8.0 (7.9–8.1)
Autism proportion	0.8 (0.7–0.8)	0.7 (0.6–0.8)	0.6 (0.6–0.7)	0.7 (0.7–0.7)
Asperger proportion	0.4 (0.3–0.5)	0.5 (0.4–0.6)	0.8 (0.7–0.9)	0.5 (0.5–0.5)
PDD-NOS proportion	0.2 (0.1–0.3)	0.1 (0.1–0.2)	0.2 (0.1–0.2)	0.1 (0.1–0.1)

PDD-NOS, Pervasive Developmental Disorders, Not Otherwise Specified.