We are a production method, and we pay taxes at the factory to calculate GDP, which is nothing more than to see if you have added value in the process of circulation. Unless you circumvent the tax bureau and the statistics department from the source, and sell it in the village in a small workshop.
The US imperialists use the expenditure method to calculate GDP, looking at consumption, not production. Lawyer's fees, training fees, and rent are all counted, and even if you buy a house by yourself, you have to discount it according to the rent.
The statistical methods are different, to put it bluntly, China's GDP caliber is different from that of most countries, according to the expenditure method, Beijing and Shanghai alone can be converted into rent GDP.
Someone in China's first economic census had the privilege of participating in it. Basically, useful data is the main body of state-owned enterprises and large enterprises that have specialized accounting personnel. (Regardless of whether there are false accounts or not). Other roadside stalls, kiosks, Internet cafes, etc. are very cooperative, and the staff of the community have obtained real data. After the survey is completed, the data will be entered into the system and you will find some interesting tables, three commissaries, with a turnover of 1000, 10000, 100000. After so many years, I don't know if there has been any improvement.