Rate of first recorded diagnosis of autism and other pervasive developmental disorders in United Kingdom general practice, 1988 to 2001

Table 1 First diagnoses of PDD by year of diagnosis and gender

Year	Number of cases			Person years at risk			Crude incidence rate (per 10000 person-years)			Male:Female incidence rate ratio	Age standardised incidence ratio (S.I.R)
	All	M	F	All	M	F	All	M	F		All	M	F
1988	1	1	0	94474	49353	45121	0.11	0.20	0	∞	8	10	0
1989	6	6	0	260978	135542	125436	0.23	0.44	0	∞	19	22	0
1990	21	20	1	643830	332819	311012	0.33	0.60	0.03	18.7	28	32	8
1991	45	36	9	1118577	576722	541855	0.40	0.62	0.17	3.8	35	34	42
1992	45	37	8	1311605	675188	636417	0.34	0.55	0.13	4.3	31	31	33
1993	69	51	18	1376111	707674	668437	0.50	0.72	0.27	2.7	47	42	72
1994	77	61	16	1432528	735395	697134	0.54	0.83	0.23	3.6	52	49	64
1995	108	97	11	1476627	756200	720427	0.73	1.28	0.15	8.4	74	79	45
1996	102	85	17	1381242	705526	675716	0.74	1.21	0.25	4.8	78	78	77
1997	133	115	18	1283151	653791	629359	1.04	1.76	0.29	6.2	114	119	89
1998	192	152	40	1228058	624723	603335	1.56	2.43	0.66	3.7	180	173	218
1999	231	193	38	1121383	568937	552446	2.06	3.39	0.69	4.9	242	244	231
2000	211	179	32	935906	474344	461562	2.26	3.77	0.69	5.4	277	284	244
2001	169	139	30	567058	287574	279483	2.98	4.83	1.07	4.5	365	361	388
All	1410	1172	238	14231526	7283787	6947739	0.99	1.61	0.34	4.8	100	100	100

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