SELECT 

    YEAR(revision.rev_timestamp) AS year, 

    COUNT(DISTINCT actor.actor_name) AS user_count

FROM page

JOIN revision 

    ON page.page_id = revision.rev_page

JOIN actor

    ON revision.rev_actor = actor.actor_id

WHERE page.page_namespace = 4

    AND page.page_title LIKE 'Articles_for_deletion/%'

    AND revision.rev_timestamp >= DATE_FORMAT(DATE_SUB(NOW(), INTERVAL 5 YEAR), '%Y%m%d%H%i%s')

GROUP BY year

ORDER BY year;