In that case, Wikipedia could use your help cleaning up this and many related articles: https://en.wikipedia.org/wiki/Illegal_drug_trade_in_China
Don't forget to cite your sources! They're sticklers about that sort of thing.
I referring to the period following the opium ban. I believe this was the 50s, not the present day. We are also comparing to an insanely high level were the claims was that 90% of inhabitants of certain provinces were users.
If you're referring to the decades since the 1950s, under a communist regime the Chinese obviously had better things to worry about (like surviving, finding a meal or looking commie enough not to be singled out by their own children and 're-educated' in some hellish camp).