For a science fiction novel it was pretty huge--selling over 125,000 copies[1] in its first couple years, and is ranked near the top 10 of all time. This list [2] has it in 12th place overall, but a lot of the others on the list have also been movies, which raises the profile of books a lot.

[1] https://www.washingtonpost.com/archive/lifestyle/1995/02/21/... [2] https://best-sci-fi-books.com/the-bestselling-science-fictio...