Prices of the area’s biggest commercial properties keep rising, and so do their taxes.

Property taxes rose at nine out of the 10 commercial properties in Cook County with the highest bills in 2013, according to the Cook County Treasurer’s Office. That’s similar to the 2012 tax year, when tax bills also mostly rose for the area’s biggest landlords.

Yet unlike 2012, when five of the most valuable commercial properties here were hit with double-digit tax increases, increases in the past year were more modest, perhaps reflecting a cooling real estate market that was red-hot throughout 2012 and into 2013. Woodfield Mall, the 2.2 million-square-foot shopping center in Schaumburg, got hit with a 23 percent tax hike, to $23 million, the biggest increase in the top 10 but the only property on the list with a double-digit increase.

The tax bills for the top 10 properties rose an average of 3.5 percent from 2012 to 2013, compared to a 7.1 percent increase from 2011 to 2012. The total 2013 commercial property tax bill is not yet available.

“Certainly the increases are ebbs and flows, but that said the trend line is up,” said Howard Ecker, CEO of Chicago-based Howard Ecker & Co., a commercial brokerage that represents tenants. “It’s not flat or down.”