given the general market trends at the time, sales of Action Comics and Superman probably peaked in the mid-1940s and thereafter steadily declined. Sales data first became public in 1960, and showed that Superman was the best-selling comic book character of the 1960s and 1970s. Sales rose again starting in 1987. Superman #75 (Nov 1992) sold over 23 million copies, making it the best-selling issue of a comic book of all time, thanks to a media sensation over the supposedly permanent death of the character in that issue. Sales declined from that point on. In March 2018, Action Comics sold just 51,534 copies, although such low figures are normal for superhero comic books in general (for comparison, Amazing Spider-Man #797 sold only 128,189 copies). The comic books are today considered a niche aspect of the Superman franchise due to low readership, though they remain influential as creative engines for the movies and television shows. Comic book stories can be produced quickly and cheaply, and are thus an ideal medium for experimentation. Whereas comic books in the 1950s were read by children, since the 1990s the average reader has been an adult. A major reason for this shift was DC Comics' decision in the 1970s to sell its comic books to specialty stores instead of traditional magazine retailers (supermarkets, newsstands, etc.) — a model called "direct distribution". This made comic books less accessible to children. Newspaper strips Beginning in January 1939, a Superman daily comic strip appeared in newspapers, syndicated through the McClure Syndicate. A color Sunday version was added that November. Jerry Siegel wrote most of the strips until he was conscripted in 1943. The Sunday strips had a narrative continuity separate from the daily strips, possibly because Siegel had to delegate the Sunday strips to ghostwriters. By 1941, the newspaper strips had an estimated readership of 20 million. Joe Shuster drew the early strips, then passed the job to Wayne Boring. From 1949 to 1956, the newspaper strips were drawn by Win Mortimer. The strip ended in May 1966, but was revived from 1977 to 1983 to coincide with a series of movies released by Warner Bros. Editors Initially, Siegel was allowed to write Superman more or less as he saw fit because nobody had anticipated the success and rapid expansion of the franchise. But soon Siegel and Shuster's work was put under careful oversight for fear of trouble