Thank you, everyone, now I understand, so the summary merit is airdrop from forum to users.
is this airdrop every year or its just one time ?
Merit summary is not air dropped merits from the forum to users. It's instead the earned merit of that user. Merits that were airdropped do not show up in the merit summary at all. Airdrop only occurred during the launch of the merit system, there would likely never be another.