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
database name:db_id authors
Author table Author Cols: Id dtype integer, Name dtype text, Affiliation dtype text, 
Conference table Conference Cols: Id dtype integer, ShortName dtype text, FullName dtype text, HomePage dtype text, 
Journal table Journal Cols: Id dtype integer, ShortName dtype text, FullName dtype text, HomePage dtype text, 
Paper table Paper Cols: Id dtype integer, Title dtype text, Year dtype integer, ConferenceId dtype integer, JournalId dtype integer, Keyword dtype text, 
PaperAuthor table PaperAuthor Cols: PaperId dtype integer, AuthorId dtype integer, Name dtype text, Affiliation dtype text, 
