Today, census data show that of the 115.4 million U.S. households, renters account for 38.5 million, or 33 percent of the total, and that the rental-vacancy rate is at its lowest point since 2001, before the housing boom's start.
What's more, the shortage of units has pushed things to a point where falling home prices and record low interest rates have made monthly mortgage payments (if you can qualify for a loan) generally cheaper than rents.
Locally, the burden is falling most heavily on those least able to handle it - low- and moderate-income Philadelphia-area residents, according to an annual study by the National Low Income Housing Coalition and the Housing Alliance of Pennsylvania.
Area households must earn $20.67 per hour, or $43,000 per year, to afford a two-bedroom apartment at what the groups consider a fair-market rent of $1,075 a month.
Meeting those costs requires a resident earning minimum wage to work 114 hours per week year-round, the study shows.
The report "illustrates the vast disparity between the cost of obtaining safe, affordable housing and the wages that many Pennsylvanians, including the disabled, elderly, and low-income residents, actually earn," said Liz Hersh, executive director of the housing alliance.
"Despite working hard and playing by the rules, these residents and their families are too often forced to settle for substandard, unsafe housing," Hersh said.
With more people choosing not to own homes, the demand for affordably priced rental housing is surging, pushing rents upward and vacancy rates down, the housing coalition's study showed.
The trends appear to have the most severe implications for extremely low-income households, meaning those earning at or below 30 percent of area median income, which in the Philadelphia region is $78,300, according to the U.S. Department of Housing and Urban Development.
Across Pennsylvania, a household must earn $16.06 per hour - more than twice the state minimum wage and roughly 125 percent of the average state renter's hourly earnings - to afford a two-bedroom apartment, the housing coalition's study showed.
With the state fair-market rent at $835 per month, households must have one minimum-wage earner working 89 hours per week year-round to afford a standard two-bedroom unit, the study showed.
And Pennsylvania is not the most expensive state. That distinction falls to Hawaii, with renters having to earn $31.68 an hour to pay for a two-bedroom apartment, almost twice that in Pennsylvania and $11 more than in metropolitan Philadelphia.
Pennsylvania ranks 21st on the list of 52, which includes Washington, D.C., and Puerto Rico. New Jersey is in fourth place at $25.04, while Delaware is 14th at $18.65 an hour, the coalition's study showed.
Fair-market rent for a two-bedroom apartment in New Jersey is $1,302 a month, the study says. The annual income needed to afford that rent is $52,081, or 40 hours of work a week by each of 3.5 minimum-wage earners.
Delaware's fair-market rent is $970 a month. The annual income needed is $38,784, requiring 2.6 minimum-wage earners to work 40-hour weeks to pay for it.
At $9.88 an hour, Puerto Rico is the least expensive, the study showed.
Fair-market rent for a two-bedroom apartment across the nation as a whole is $949. A renter earning the federal minimum wage of $7.25 must work 101 hours to afford it.
What such a renter could actually afford to pay, working a regular 40-hour week, is $377 a month, the data show.
"For extremely low-income Americans, including those on fixed incomes, finding an affordable, decent apartment continues to be incredibly challenging," the coalition said.
Contact Alan J. Heavens
at 215-854-2472, email@example.com or @alheavens at Twitter.