According to Mendlesohn in his Short History of Fantasy, Fantasy became the most popular Speculative Fiction subgenre occupying two$-$thirds of all speculative fiction sales

According to Mendlesohn in his Short History of Fantasy, Fantasy became the most popular Speculative Fiction subgenre occupying two$-$thirds of all speculative fiction sales

sometime in the $1980\text{'}$s$.$

sometime in the $1970\text{'}$s

in ancient times since it has always been the most popular genre.

sometime in the $1990\text{'}$s