What is the average number of papers published in the World Computer Congress each year?
published in the World Computer Congress refers to FullName = 'World Computer Congress'; average refers to DIVIDE(COUNT(FullName = 'World Computer Congress'), COUNT(Id))
SELECT CAST(SUM(CASE WHEN T2.FullName = 'International Congress Series' THEN 1 ELSE 0 END) AS REAL) / COUNT(T1.Id) AS Div1, T1.Year FROM Paper AS T1 INNER JOIN Journal AS T2 ON T1.JournalId = T2.Id GROUP BY T1.YEAR HAVING Div1 != 0