What is the decomposition basis of social security?

Yes, and that person had better go through the formalities of downsizing at once.

At the end of the year, it is detailed according to the amount of social security paid by the unit to the tax authorities every month. After the end of the year, the tax authorities will transmit the data to the social security company. The social security company decomposes according to this data (the number of months is the same, and these cannot be changed).