Kathy Kmonicek/AP
Jimmy McMillan, candidate for Rent is 2 Damn High party makes a point during the 2010 New York State Gubernatorial debate held at Hoftstra University in Hempstead, N.Y.
That's because it's getting harder for them to find available and affordable apartments that they would want if they choose to move.
RealPage provides property-management software for rental housing. Its analysis of 10 million units this year found that the renewal rate was 53.8%, inching up slightly from 52.9% in 2015 and 51.7% in 2014.
"People are renting what they can afford and that means they might have to make some compromises on neighborhood or product quality, but they are not spending a much bigger share of income on rent than they historically have," Greg Willett, RealPage chief economist, told Business Insider.
The top five markets with the highest retention rates from January to July were Northern New Jersey, Milwaukee, Cleveland, New York, and Philadelphia.
"Until we reach the point where people start doubling up, or are just seeking out other housing options, that would suggest that rents are pricing to go higher," Willett said.
The same imbalance of demand and supply that's reducing affordability for homeowners is hitting renters as well. According to the Census Bureau, the rental vacancy rate in the second quarter was 6.7%, matching the lowest level since the fourth quarter of 1985.
Shelter costs have recently been the biggest driver of inflation measured by the consumer price index (CPI). Owners' equivalent rent - the value of shelter for homeowners derived by comparing it to rentals - is the largest subcomponent of the shelter index. And it makes up 32% of the overall consumer-price basket that CPI is based on.