Chicago teachers get paid, on average, over 74k per year. Over half the CPS operational budget is dedicated to salaries and benefits for CPS employees and the per pupil spending is just over 13k, which makes it the most expensive public school system in the country (after New York and DC).
Source: Chicago Public Schools
They're being offered a guaranteed raise of 16% over 4 years and they rejected it because they're concerned about teacher accountability.
That is an act of true cowardice. I hope the Chicago Teachers Union gets everything that's coming to them. This is why government employees shouldn't be allowed to collectively bargain. They enrich themselves and select politicians at the expense of the public.