[Bug Report] 2018 attendee data in bigquery needs to review

[tai271828]

Description

In 2021's retro, the data team represents the attendee-based information. The total numbers look inconsistent with the data shown on kktix. Maybe the data duplicated when we re-setup the table schema.

I am not sure where is a better place to record this issue. Let me create the corresponding issue here first.

More Information

The discord thread for more context https://discord.com/channels/752904426057892052/909358515083153449/909358856629538836