First published by Money Metals here: https://www.moneymetals.com/news/2018/10/02/silver-eagle-sales-september-spike-001628

Demand for the U.S. Mint Silver Eagles spiked again at the end of the September pushing sales nearly to three million. In a little more than a week, Silver Eagle sales jumped from 1.9 million to 2.9 million, nearly doubling from the previous month. Sales of Silver Eagles in August were only 1.5 million versus 2.9 million in September.