"Walter Freeman performed about 3,500 lobotomies in 23 states during 
his career of which 2,500 were his ice-pick procedure."

http://listverse.com/2009/06/24/top-10-fascinating-and-notable-lobotomies/

"Freeman's ice-pick lobotomy became wildly popular.  ... The U.S. 
performed more lobotomies than any other country."

http://psychcentral.com/blog/archives/2011/03/21/the-surprising-history-of-the-lobotomy/

www.peoplewho.org