Renay of Lady Business (and her aarmy of helpers) has done a really good job in getting this information today.
These graphs and this information are irrefutable evidence that there IS an issue of bias in SFF awards:
SFF Awards have a problem. Despite some gains towards diversity in recent years, books by and about cis men still dominate nearly all the major awards. The gains in recent years have been encouraging, but they’re offset by long histories of privileging cis men and their writing over cis women and trans and nonbinary individuals. Most of the longest-running awards have heavily male-dominated histories. Let us be clear that this is not because cis men produce superior work. Despite their difficulty in getting published and publicized, cis women and trans and nonbinary individuals have been putting out quality work for as long as they’ve been getting published. But the SFF field by and large prefers to recognize and award books by and about cis men.