The median apartment rent ticked up by almost 5 percent since last year in the 163-acre downtown area that straddles the south branch of the Chicago River, leapfrogging River North to become the most expensive slice of the Midwest.

ZIP Code 60606, which includes the Willis Tower, Union Station and the Lyric Opera building, hit a median rent of $2,707 in July, according to a report published by RentCafe based on data from Yardi Matrix.

It was followed by ZIP codes 60654 (River North), 60611 (Streeterville) and 60601 (Lakeshore East), whose July median rents respectively climbed by 1.3 percent, 1.5 percent and 0.2 percent between year over year.

The eight highest-rent ZIP codes in the Midwest are all in or near downtown Chicago, according to the report. The ninth-highest is in downtown Minneapolis, and the tenth is the Chicago suburb of Barrington.

Another report from RentCafe found 73 percent of the residents of the West Loop are Millennials, giving it the highest proportion of young adults out of any ZIP code in the country’s 30 largest cities.

In raw numbers, Chicago is home to five of the country’s seven most Millennial-populous ZIP codes, according to that report, which defines the generation as those born between 1977 and 1996.

ZIP code 60607, which fully encompasses Fulton Market, registered a 2.5 percent bump in median rent since last year to reach $2,295, making it the eighth-most expensive in the Midwest.

In ZIP code 60606, where the median apartment rent is highest in the Midwest, Riverside Investment & Development this week presented a revised proposal for its redevelopment of Union Station that cut all 404 apartments that had been originally planned.

Not far away in the Willis Tower, the Blackstone Group announced it would include a new food hall in the 300,000-square-foot addition it’s building at the base of the skyscraper.