What is the proportion of the papers that have the keyword "cancer"? Please provide a list of authors and their affiliations.
Proportion refer to DIVIDE(COUNT(Keyword = ’cancer’), COUNT(PaperID))
SELECT CAST(SUM(CASE WHEN T1.Keyword = 'cancer' THEN 1 ELSE 0 END) AS REAL) / COUNT(T1.Id), T2.Name, T2.Affiliation FROM Paper AS T1 INNER JOIN PaperAuthor AS T2 ON T1.Id = T2.PaperId