Since gmail has minimum password length of 8, my random guess is that 90% of the users have passwords between 8 and 15. Does knowing the precise length of the p

Since gmail has minimum password length of 8, my random guess is that 90% of the users have passwords between 8 and 15. Does knowing the precise length of the password buys the attacker so much that they can now guess the passwords of 10% users? Also, note that they do not know the username that corresponds to the given password length. Without more details, I seriously doubt this claim.