Major US cities saw median rent fall last month.Annex on 12th Rent edged lower in September, continuing a long streak of year-over-year declines. Southern cities saw some of the largest dips in rent. Here are 24 real-estate markets where rent is at least 10% below the national median. Apartment dwellers scored a small but much-needed win on the affordability front in September.Median rent in the 50 largest US metropolitan areas dipped to $1,743 last month, according to an October 16 report from Realtor.com.