Among all the citation, what is the percentage of paper ID under the Agents classification?
classification refers to class_label; class_label = 'Agents'; percentage = (divide(count(paper_id where class_label = 'Agents')), (count(paper_id)))*100;
SELECT CAST(COUNT(CASE WHEN class_label = 'Agents' THEN paper_id ELSE NULL END) AS REAL) * 100 / COUNT(paper_id) FROM paper