The lowest-income renters, those with incomes below about $18,946, make up 27.6 percent of renters in Cook County and 79 percent of them are devoting half or more of their income to rent, according to Smith. That's creating a serious rent burden for them. Renters with incomes under $31,500 also are facing burdens because they are spending more than they should on rent. Over 85 percent of them are devoting more than 30 percent of their income to rent. The median household income in Cook County is $63,153.