What is the percentage of the actors that showed up in the credit list of movie "Dawn of the Planet of the Apes" that were born after "1970/1/1"?
movie "Dawn of the Planet of the Apes" refers to Title = 'Dawn of the Planet of the Apes'; born after "1970/1/1" refers to Date of Birth > '1970/1/1'; percentage = divide(count(ActorID where Date of Birth > '1970/1/1'), count(ActorID))*100%
SELECT CAST(SUM(CASE WHEN T3.`Date of Birth` > '1970-01-01' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T3.`Date of Birth`) FROM movie AS T1 INNER JOIN characters AS T2 ON T1.MovieID = T2.MovieID INNER JOIN actor AS T3 ON T3.ActorID = T2.ActorID WHERE T1.Title = 'Dawn of the Planet of the Apes'