-- Database schema
| Question : questiontext [ TEXT ] , questionid [ INTEGER ] primary_key | Survey : SurveyID [ INTEGER ] primary_key , Description [ TEXT ] | Answer : AnswerText [ TEXT ] , SurveyID [ INTEGER ] , UserID [ INTEGER ] , QuestionID [ INTEGER ] |
-- -- What was the percentage for the answer of "Yes" was given to the question "Has your employer ever formally discussed mental health (for example, as part of a wellness campaign or other official communication)?"?

SELECT CAST(SUM(CASE  WHEN T1.AnswerText LIKE 'Yes' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.UserID) FROM Answer AS T1 INNER JOIN Question AS T2 ON T1.QuestionID = T2.questionid WHERE T2.questiontext LIKE 'Has your employer ever formally discussed mental health (for example, as part of a wellness campaign or other official communication)?';