How many DNS Names are, on average, in each certificate issued by Let's Encrypt?

AvgNumberOfNames.sql

SELECT
    AVG(count)
FROM
    (SELECT
        c.certID,
            (SELECT
                    COUNT(n.name)
                FROM
                    name AS n
                WHERE
                    n.certID = c.certID) AS count
    FROM
        le_current_certificate AS c) AS a;

AvgNumberOfNames.tsv

AVG(count)
3.7804