The ETIS, set up by CITES, counts only the ivory it finds, which is a tiny, tiny amount of the overall trade in illegal ivory. Poachers do not register their ivory with ETIS. Most of that ivory goes to China to make trinkets or products that come back to the US. CITES has given China "Approved Buyer" status, which shows that CITES is a corrupt organization heavily influenced by the business people it supposedly regulates. Saying China is a responsible buyer of ivory is like saying the Japanese whaling fleet is really doing nothing more than scientific research. (And, speaking of Japan, more than 100,000 pounds of illegal ivory was recently seized there.)
We also know, and I've posted links, that tons of illegal ivory are seized in the US, despite an enforcement effort that is almost helpless. The tons of illegal ivory seized in the US are the tip of the iceberg, and those seizures don't even count all the illegal ivory that cannot be proven illegal without expensive, destructive testing.
The truth is that elephants are being slaughtered at a horrendous rate. If the slaughter is not stopped, we'll lose elephants in the wild. And a huge percentage of that illegal ivory is going to consuming nations, including the United States.