The above figures are presumably based on the fighter salary information that promoters are required by law to submit to the state athletic commissions, including the winners' bonuses.
The figures do not represent a full accounting of each fighter's income.
Fighters bear significant costs including training expenses, a percentage to management, a percentage to the trainer, plus insurance, licenses, and taxes.
On the income side, sponsorship money can be a substantial portion, or even exceed the purse from the fight. As well there are explicit 'of the Night' performance bonuses, and less formal 'locker room bonuses.'
Lastly, many fighters earn income from teaching, from appearances, and in many cases from regular employment in the non fighting space.