CHICAGO (CBS)–Illinois residents pay an average of $331 per year in taxes for cell phone usage–thanks the highest wireless tax of any other U.S. state, the Illinois Policy Institute says.

The $331 a year in taxes is for a cellphone bill for the typical Illinois household that pays $100 a month for four wireless lines.

Citing a report from the nonpartisan Tax Foundation, the Illinois Policy Institute says new tax increases in Chicago and statewide contributed to an increase that boosted Illinois from the fourth-highest state for cell phone taxes to the very top of the list.

In Illinois, the wireless tax rate is 27.6 percent, according to the Illinois Policy Institute. That’s compared to a nationwide average of $19.1 percent–or $229 per year.

Chicago residents pay even more. The average tax bill for a four-line, $100 per month plan for a Chicago cell phone user is $488, the study says.

As for why the state has such high cell phone taxes, the Tax Foundation says 911 fee hikes in Chicago and at the state level are to blame.

Last year, Illinois lawmakers voted to override Gov. Bruce Rauner’s veto of a bill that increased the state’s 911 fee from 87 cents per line per month to $1.50. The bill, which took effect this year, allowed Chicago to increase its 911 fee to $5 from $3.90 per line per month, according to the Illinois Policy Institute.