Tesla more than doubled its sales volume in China last year (161%). This year might triple or quadruple its sales.
According to Tesmanian, citing China Automotive Information Net's data, Tesla's new car registrations rose to 6,643 in December. That's of course without much of a contribution from the Tesla Gigafactory 3, because customer deliveries are only just ramping-up from January 2020.
In 2019, the total number of Tesla registrations increased by 161% year-over-year, from 16,360 to 42,715.
That's a lot, but still just a fraction of 367,500 sales globally, and far from the European level yet (probably above 100,000). The Chinese position is expected to improve in 2020, when the Made-in-China (MIC) Model 3 will reach full scale.
There is a big chance that we will see more than 10,000 sales a month in Q1, and more than 100,000 sales in 2020 total. How much "more" above 100,000 is an open question.