What is the average of Indian players that were born between 1975 and 1985 among all players?
Indian players refers to Country_Name = 'India'; born between 1975 and 1985 refers to strftime('%Y',T1.DOB) between '1975' and '1985'; average refers to DIVIDE(COUNT(Country_Name = 'India'), COUNT(Player_Id))
SELECT CAST(SUM(CASE WHEN T2.Country_Name = 'India' THEN 1 ELSE 0 END) AS REAL) / COUNT(T1.Player_Id) FROM Player AS T1 INNER JOIN Country AS T2 ON T1.Country_Name = T2.Country_ID WHERE strftime('%Y', T1.DOB) BETWEEN '1975' AND '1985'