What is the real estate tax in Illinois?

The Illinois constitution mandates property taxes. All property in Illinois is supposed to be taxed on an assessed value of 1/3 of the fair cash value. Once the value is established, then in all counties except Cook (where Chicago is), property is supposed to have an assessed value of 1/3 of the fair cash value. In all Counties except Cook, this is figured every year. This is then multiplied by a State "equalization factor" announced annually to attempt bring the value to a "true" assessed value (so in a county where property is typically accurately assessed the factor will be 1.0 theoretically, but in a County like Cook where there is a different assessed value system, the factor can be 2 or even in recent years close to 3). Then the tax rate is applied; the tax rate is a combination of all the tax rates of all the taxing districts where you live (schools, local governments, county government, parks, etc.). There are certain exemptions (homeowner/occupant, senior) and certain tax incentives (historic, improvements...) but these are the basics. In Cook County, there is a tiered system for 2 reasons: there are so many properties only 1/3 of the county is reassessed at a time instead of all annually, and therefore 2/3 of the county "lags behind" at any given time. Secondly, instead of the flat 1/3 of fair cash value, residential and vacant properties are all at 10% of fair cash value, and all commercial and industrial properties are at 25% of fair cash value. You can see how in Cook a residential property given a fair cash value of $120,000 would have an assessed value @ 10% of $12,000 and to "equalize" it back to the required 1/3 of fair cash value, the equalizer have to be close to about 3.3, meaning the "true" equalized assessed value would be $36,000. Why it is so convoluted is political.....