▁in ▁the ▁aut ism ▁category ▁would ▁probably ▁have ▁been ▁counted ▁in ▁the ▁mental ▁ret ard ation ▁or ▁learning ▁dis abilities ▁categories ▁if ▁they ▁were ▁being ▁l abeled ▁ 1 0 ▁years ▁ago ▁instead ▁of ▁today ," ▁said ▁research er ▁Paul ▁Sh att uck ▁of ▁the ▁W ais man ▁Center ▁at ▁the ▁University ▁of ▁Wisconsin – Mad ison , ▁in ▁a ▁statement . ▁ ▁A ▁population - based ▁study ▁in ▁Ol m sted ▁County , ▁Minnesota ▁county ▁found ▁that ▁the ▁cum ulative ▁inc idence ▁of ▁aut ism ▁grew ▁eight fold ▁from ▁the ▁ 1 9 8 0 – 8 3 ▁period ▁to ▁the ▁ 1 9 9 5 – 9 7 ▁period . ▁The ▁increase ▁occurred ▁after ▁the ▁introduction ▁of ▁bro ader , ▁more - prec ise ▁di agnostic ▁criteria , ▁increased ▁service ▁avail ability , ▁and ▁increased ▁aw aren ess ▁of ▁aut ism . ▁During ▁the ▁same ▁period , ▁the ▁reported ▁number ▁of ▁aut ism ▁cases ▁grew ▁ 2 2 - fold ▁in ▁the ▁same ▁location , ▁suggesting ▁that ▁counts ▁reported ▁by ▁clin ics ▁or ▁schools ▁provide ▁mis leading ▁estimates ▁of ▁the ▁true ▁inc idence ▁of ▁aut ism . ▁ ▁Venezuela ▁A ▁ 2 0 0 8 ▁study ▁in ▁Venezuela ▁reported ▁a ▁pre val ence ▁of ▁ 1 . 1 ▁per ▁ 1 , 0 0 0 ▁for ▁aut ism ▁and ▁ 1 . 7 ▁per ▁ 1 , 0 0 0 ▁for ▁AS D . ▁ ▁Asia ▁A ▁journal ▁reports ▁that ▁the ▁median ▁pre val ence ▁of ▁AS D ▁among ▁ 2