Who coined the term hump day?

The author was Walter E. Hisaw, a blue-print specialist at Ingles Shipyard, Land Based Test Facility, Pascagoula Mississippi in 1973. He captioned a cartoon he had drawn about Wednesdays being a milestone of the work week. The cartoon was inspired by the overuse of the recently-popular "TGIF" by his coworkers. His cartoon went world-wide as Fax machines were just coming into use and was a popular method for engineers and technicians to share jokes and Cartoons. Walter Hisaw was also the author/cartoonist for a drawing of a mushroom (with human features) seated at a drafting table and captioned "I feel like a mushroom because they keep me in the dark around here. " This second cartoon became iconic when an unknown fax-user edited the caption to read "I feel like a mushroom around here becuase they keep me in the dark and feed me bull-sh-t!"