▁bro aden ing ▁di agnostic ▁criteria . ▁Studies ▁based ▁on ▁more ▁detailed ▁information , ▁such ▁as ▁direct ▁observation ▁rather ▁than ▁exam ination ▁of ▁medical ▁records , ▁identify ▁higher ▁pre val ence ; ▁this ▁suggests ▁that ▁published ▁figures ▁may ▁under est imate ▁AS D ' s ▁true ▁pre val ence . ▁A ▁ 2 0 0 9 ▁study ▁of ▁the ▁children ▁in ▁Camb rid ges hire , ▁England ▁used ▁different ▁methods ▁to ▁measure ▁pre val ence , ▁and ▁estimated ▁that ▁ 4 0 % ▁of ▁AS D ▁cases ▁go ▁und i agn osed , ▁with ▁the ▁two ▁least - bi ased ▁estimates ▁of ▁true ▁pre val ence ▁being ▁ 1 1 . 3 ▁and ▁ 1 5 . 7 ▁per ▁ 1 , 0 0 0 . ▁ ▁A ▁ 2 0 0 9 ▁U . S . ▁study ▁based ▁on ▁ 2 0 0 6 ▁data ▁estimated ▁the ▁pre val ence ▁of ▁AS D ▁in ▁eight - year - old ▁children ▁to ▁be ▁ 9 . 0 ▁per ▁ 1 , 0 0 0 ▁( appro xim ate ▁range ▁ 8 . 6 – 9 . 3 ). ▁A ▁ 2 0 0 9 ▁report ▁based ▁on ▁the ▁ 2 0 0 7 ▁Ad ult ▁Psych iat ric ▁Mor bid ity ▁Survey ▁by ▁the ▁National ▁Health ▁Service ▁determined ▁that ▁the ▁pre val ence ▁of ▁AS D ▁in ▁adult s ▁was ▁approximately ▁ 1 % ▁of ▁the ▁population , ▁with ▁a ▁higher ▁pre val ence ▁in ▁males ▁and ▁no ▁significant ▁variation ▁between ▁age ▁groups