Now that you mention it, I was somewhat curious.  I ran the following simple query on both Super User and Stack Overflow to see how many users had edit permission (>= 2000 reputation):

    SELECT
        COUNT(*)
    FROM
        Users
    WHERE 
        Users.Reputation >= 2000

Which returns 488 for Super User, and 18890 for Stack Overflow.  As a percentage of total users (i.e. commenting out the `WHERE` clause in the above query), and repeating the query for Android SE while we're at it, we get:

    Super User:     (  488 /  136571) x 100% = 0.357%
    Stack Overflow: (18890 / 1582958) x 100% = 1.193%
    Android SE:     (   32 /   19260) x 100% = 0.166%

Given these numbers, it appears as though Super User has roughly 3.3 times *less* editors as a percentage of all users on the site as compared to Stack Overflow.