SELECT
    year,
    count(*) AS cnt
FROM (
    SELECT
        event_timestamp,
        DATE_FORMAT(event_timestamp, 'yyyy') AS year,
        event_user_text,
        user_text,
        event_comment
    FROM
        mediawiki_history
    WHERE
        snapshot='2018-11'
        AND wiki_db='enwiki'
        AND event_entity='user'
        AND event_type='alterblocks'
        AND event_user_text=user_text
    ) x
GROUP BY year
ORDER BY year ASC
LIMIT 100;