英訳に間違いが有れば正してください。
白人の86％が自分の親友は白人であると答え、調査した黒人住民の70％は自分の親友が黒人であると報告しました。
Eighty-six percent of white people said their closest friends were white, and 70% of black residents survey reported that their best friends were black.
ヒント
主語の形
答え surveyをsurveyedにする
Eighty-six percent of white people said their closest friends were white, and 70% of black residents surveyed reported that their best friends were black.
residents survey reportedの並びでおかしいと分かる
調査された住民（residents surveyed）が報告したという、人が主語の文。
調査（survey）が報告したという無生物主語でない。
They released results of a resident survey.
彼らは住民調査の結果を発表した。
住民調査という意味の場合residentは単数になる。
“Eighty-six percent of white people said their closest friends were white, and 70% of black residents surveyed reported that their best friends were black.”
引用元
THE CONVERSATION
How dogs help keep multiracial neighborhoods socially segregated
May 22, 2019 10.04pm AEST
http://theconversation.com/how-dogs-help-keep-multiracial-neighborhoods-socially-segregated-116120
