; ▁these ▁results ▁suggest ▁that ▁pre val ence ▁of ▁AS D ▁among ▁adult s ▁is ▁similar ▁to ▁that ▁in ▁children ▁and ▁rates ▁of ▁aut ism ▁are ▁not ▁increasing . ▁ ▁Ch anges ▁with ▁time ▁Att ention ▁has ▁been ▁focused ▁on ▁whether ▁the ▁pre val ence ▁of ▁aut ism ▁is ▁increasing ▁with ▁time . ▁Ear lier ▁pre val ence ▁estimates ▁were ▁lower , ▁cent ering ▁at ▁about ▁ 0 . 5 ▁per ▁ 1 , 0 0 0 ▁for ▁aut ism ▁during ▁the ▁ 1 9 6 0 s ▁and ▁ 1 9 7 0 s ▁and ▁about ▁ 1 ▁per ▁ 1 , 0 0 0 ▁in ▁the ▁ 1 9 8 0 s , ▁as ▁opposed ▁to ▁today ' s ▁ 1 5 – 1 7 ▁per ▁ 1 0 0 0 . ▁▁ ▁The ▁number ▁of ▁reported ▁cases ▁of ▁aut ism ▁increased ▁dram atically ▁in ▁the ▁ 1 9 9 0 s ▁and ▁early ▁ 2 0 0 0 s , ▁prompt ing ▁investig ations ▁into ▁several ▁potential ▁reasons : ▁ ▁More ▁children ▁may ▁have ▁aut ism ; ▁that ▁is , ▁the ▁true ▁frequency ▁of ▁aut ism ▁may ▁have ▁increased . ▁ ▁There ▁may ▁be ▁more ▁complete ▁pick up ▁of ▁aut ism ▁( case ▁finding ), ▁as ▁a ▁result ▁of ▁increased ▁aw aren ess ▁and ▁fund ing . ▁For ▁example , ▁attempts ▁to ▁sue ▁v acc ine ▁companies ▁may ▁have ▁increased ▁case - report ing . ▁ ▁The ▁diagn osis ▁may ▁be ▁applied ▁more ▁broad ly ▁than ▁before , ▁as ▁a