I was doing a little checking on the master serial number pages. The 221 began production in 1933. Through to the beginning of 1940, there were serial numbers allotted for manufacturing the 221 to the tune of 250,000. Just because the list says there were "20,000 made on June 5" only means they allocated that many serial numbers to that plant. It doesn't mean they were all made on that day. It may take a plant a few months to make that many machines. Based on that quantity in just 7 years, and the fact that they produced these jewels thru 1968, I would guess that several million Featherweights were built. I do not understand why these machines are so expensive, considering there were approx. 4 million made and the fact these machines are so durable and long lasting. However, I love my Featherweights and use them all the time.