Average rents in Des Moines increased 1.5 percent in January from a year earlier, leaving the city with the distinction of having the most robust boost in rental rates in the state, according to a report from RentCafe. Regardless of whether the location is Des Moines or Council Bluffs, Iowa rents were not among the highest or lowest in the country. According to the report, Ankeny and Johnston are among the steepest rents in the state, with average rent running around $1,100 a month, yet rent increases in those cities were nearly stagnant — 0.9 percent year over year in Ankeny and 0.5 percent in Johnston. The national average rent remained flat month-to-month, reaching $1,420 in January, with a year-over-year increase of 3.3 percent or $45, according to data from Yardi Matrix.