Lope de Vega 1562-1635) wrote 2200 works in his lifetime, of which 500 survive. 

Alexandre Dumas pere (1802-1870) produced works that run to 1500 volumes. 

Annie S. Swan (1860-1943) managed to write 183 novels. 

Hilaire Belloc (1870-1953) issued over 100 titles. 

Dorothy Richardson (1873-1957) had a sustained fictional output of a twelve-volume stream-of-consciousness novel (1915-1938). After her death, a thirteenth volume was discovered. 

Edgar Wallace 1875-1932) wrote over 170 novels and plays; in his heyday he averaged six major books a year. 

Charles Hamilton, alias Frank Richards (1875-1961) for over thirty years produced 11 million words annually, mostly as Frank Richards, but also under twenty-four other pennames. 

Ruby M. Ayers (1883-1933), in a relatively short life, produced 143 novels. 

Ursula Bloom (1892-1984) published 420 books out of 468 written. 

Denise Robins (?-1985) published 162 books. 

Barbara Cartland (1901- ) has had over 150 books published. 

Kathleen Lindsay (1903-1973) clocked up 904 novels, writing under six pennames. 

Georges Simenon (1903-?) wrote over 400 novels, 200 as Simonen and the rest under twenty-three pennames. 

John Creasey (1908-1973) published 565 books (some say more), under his own name and twenty-five pennames. 

Anyone who has taken any writing workshops or attended any writers' conference, has no doubt heard over and over again, "If you want to be a writer--write." You have to produce the words to get a finished product. 
 

Comments on Production

"Nine out of ten writers, I am sure, could write more. I think they should and, if they did, they would find their work improving even beyond their own, their agent's, and their editor's highest hopes." 

"Talent is a matter of quantity; talent doesn't write one page, it writes three hundred."

"Thinking is the activity I love best, and writing to me is simply thinking through my fingers. I can write up to 18 hours a day. Typing 90 words a minute, I've done better than 50 pages a day. Nothing interferes with my concentration. You could put on an orgy in my office and I wouldn't look up - well, maybe once."

Just What Counts as "Writing Time?"

It's natural to look at words or pages in-hand to assess writing production. However, feeding the mind of the muse is also part of the writing effort. Research time-- revision time--proofreading time--thinking time--are as much a part of writing as is time spent tapping fingers on the keyboard. 

Dylan Thomas was once asked if he had done any work that day. He replied, "Yes. I spent the morning putting in a period--and the afternoon taking it out."