Question: When was the character Beverly Marsh created in the novel of It?

Context articles: Dr. Heinz Doofenshmirtz
It (2017 film)
Naomi Clark
Ferb Fletcher
Roderick Alleyn
Sophia Lillis
Emily Perkins
Vintage Murder
Annette O'Toole
Photo Finish (novel)

Dr. Heinz Doofenshmirtz (often called "Doofenshmirtz", or occasionally "Doof") is a fictional character from the American animated television show "Phineas and Ferb".
 He was created by Dan Povenmire and Jeff "Swampy" Marsh, and is voiced by Povenmire.
 The character first appeared in the pilot episode of the series and appears in the majority of episodes.
 He is described as an incompetent and forgetful evil scientist intent on conquering the "entire tri-state area" by creating obscure but nefarious inventions.
 Dr. Doofenshmirtz speaks with a caricature of a German accent and is from the fictional European country Drusselstein.
It: Chapter One, or simply It, is a 2017 American supernatural horror film directed by Andy Muschietti, based on the 1986 novel of the same name by Stephen King.
 The screenplay is by Chase Palmer, Cary Fukunaga and Gary Dauberman.
 The first of a planned duology, the film tells the story of seven children in Derry, Maine, who are terrorized by the eponymous being, only to face their own personal demons in the process.
 The novel was previously adapted into a 1990 miniseries.
Naomi Clark, played by AnnaLynne McCord, is a fictional character from the CW primetime drama "90210", the fourth series of the "Beverly Hills, 90210" franchise.
 The character was created by Rob Thomas, Gabe Sachs, and Jeff Judah, with later developments by Rebecca Sinclair, and occasional input from McCord.
Ferbs "Ferb" Fletcher is a British character on the animated television series "Phineas and Ferb."
 The character, voiced by British actor Thomas Sangster, was created by "Phineas and Ferb" co-founders Dan Povenmire and Jeff "Swampy" Marsh and first appeared in the show's pilot episode, "Rollercoaster."
Roderick Alleyn is a fictional character who first appeared in 1934.
 He is the policeman hero of the 32 detective novels of Ngaio Marsh.
 Marsh and her gentleman detective belong firmly in the Golden Age of Detective Fiction, although the last Alleyn novel, "Light Thickens", was published in 1982.
Sophia Lillis (born February 13, 2002) is an American film and television actress.
 She is best known as the character Beverly Marsh in "It: Chapter One", a feature film adaptation of Stephen King's horror novel "It".
Emily Jean Perkins (born May 4, 1977) is a Canadian actress, best known for her roles as Crystal Braywood in the TV series "Hiccups", young Beverly Marsh in "Stephen King's It", and Brigitte Fitzgerald in "Ginger Snaps".
 Since the late 1980s she has appeared in various films and television series.
Vintage Murder is a detective novel by Ngaio Marsh; it is the fifth novel to feature Roderick Alleyn, and was first published in 1937.
 The plot centers on a traveling theatrical troupe in New Zealand.
 One of the cast members was a minor character in "Enter a Murderer", and refers to that case early in the story.
Annette O'Toole (born April 1, 1952) is an American actress, dancer, and singer-songwriter.
 She is best known for portraying Beverly Marsh in the "It" miniseries, Lana Lang in "Superman III" and more recently for portraying Martha Kent, the mother of Clark Kent, on the television series "Smallville".
Photo Finish (novel) is a detective novel by Ngaio Marsh; it is the thirty-first, and penultimate, novel to feature Roderick Alleyn, and was first published in 1980.
 The novel takes place on a millionaire's private island in New Zealand, and features the world premiere of an opera entitled "The Alien Corn", after the Biblical story of Ruth.
 The novel's central character bears a striking resemblance to Maria Callas.