Q: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Passage: The firm continued to pressure Kelsey and the agency to approve the applicationuntil November 1961, when the drug was pulled off the German market because of its association with grave congenital abnormalities. Several thousand newborns in Europe and elsewhere suffered the teratogenic effects of thalidomide. Though the drug was never approved in the USA, the firm distributed Kevadon to over 1,000 physicians there under the guise of investigational use. Over 20,000 Americans received thalidomide in this "study," including 624 pregnant patients, and about 17 known newborns suffered the effects of the drug.[citation needed]
A:
How many Americans were given the drug thalidomide?