The average ratings for blitz and bullet are ~1135, the average rating for Standard correspondence is ~1385. The curve for standard correspondence is skewed toward the higher ratings too.
Chances are that the average person's correspondence rating is at least 200 points higher than their blitz/bullet chess ratings.
Is a sustained rating in blitz or bullet considered the equivalent of a higher rating in slower or non-clocked modes of playing chess? Or are the styles considered too different to really compare?