First gas, then heating and now rents. Runaway inflation is driving rents skywards across America, delivering an average of a 20 percent increase in the U.S.'s biggest 50 cities over the past 12 months, a study details. The rent spike has stung wallets nowhere more than in the Miami metro area, where the median rent surged to an eyewatering $2,850, 49.8 percent higher than the previous year. Other cities across Florida — Tampa, Orlando and Jacksonville — and the Sun Belt destinations of Texas and Tennessee, all saw spikes of more than 25 percent in some cities during that time period. Rising rents and high inflation are moving hand-in-hand to become one of the nation's top economic problems. Economists worry about the impact of rent increases on inflation because the big jumps in new leases feed into the U.S. consumer price index, which is used to measure inflation.