DC published 3,397 comics in the 1950s and upped that to 3,579 comics in the 1960s. Despite the reasonable similarity in overall numbers, DC published dramatically different lines of comics in the 1950s versus the 1960s.
I broke the titles down into various genres: Superhero, Adventure, Science Fiction, Crime/Detective, Comedy, Western, Funny Animal, War, Horror, Teen and Romance. DC published far more Superhero books than any other genre. There were 849 Superhero books in the 1950s, or almost exactly a quarter of DC's total output. Following the Superhero revival of the late 1950s-early 1960s the Superhero genre exploded with 1,628 comics in the 1960s, over 45% of the total.
Funny Animal, which had been the second largest genre for DC in the 1950s with 533 issues, crashed all the way to 63 books in the 1960s, the lowest output of any genre for that decade. But what there was, was choice: The Fox & the Crow, a terrific series. Trivia quiz: Can you name the DC title that had one issue in the 1940s, one issue in the 1960s, and was published for the entire decade of the 1950s? Answer at end of post.
Crime/Detective was zeroed out after accounting for 172 comics in the 1950s (Gangbusters, Big Town, Mr District Attorney). Western also had a precipitous fall, from 297 issues in the 1950s to 89 in the 1960s (with most of those coming from Tomahawk).
Genres showing improvement in the 1960s included Romance (243 comics in the 1950s to 460 in the 1960s) & War (379-477). However, War titles were on the decline after 1965, dropping from 56 that year to 31 issues in 1969.
Science fiction was nominally unchanged, with 167 issues in the 1950s and 169 in the following decade. But by the end of the 1960s Mystery in Space had been cancelled and the two Sci-Fi mags published by DC were dedicated to reprints.
Comedy was also on tottering legs. The long-running DC titles in the 1960s were Jerry Lewis and Bob Hope, two film stars who had reached the end of those phases of their careers. Hope's comic was jettisoned in 1968, and Lewis would follow a few years later. Teen titles, which had never been a big part of DC's lineup as that market was dominated by Archie, declined by 50%.
Trivia Answer: Peter Porkchops' first issue was dated Nov/Dec 1949, and his last issue was Oct/Dec 1960.