According to an Illinois State Board of Education (ISBE) report, local property tax contributions to public school funding are 50% of the total.
Property tax provides about 53% of all school revenues. The property tax is the largest single source of revenue for Illinois public schools. This tax consists of the real estate tax, which is a tax on the real property of homeowners and businesses.
More than half of your property taxes go towards funding local schools in Illinois (Cook County). Depending on some townships and municipalities, it could be even more than that.