From a January 18, 2013 Wall Street Journal article titled Apartments Lift Construction Report:
Builders started construction at a seasonally adjusted annual rate of 954,000 units in December, the highest pace of construction since June 2008. The December gain was up 12% from November and 37% from the same month a year ago.
The increase was led by a surge in apartment construction, with starts up 116% for buildings with five or more units. Developers of such buildings, which make up 35% of all new residential construction, anticipate that demand for rental housing will keep growing in coming years…
Mark Vitner, senior economist at Wells Fargo, WFC -0.83% said that absorption of apartments, or the rate at which new units become occupied by renters once completed, is still well ahead of the rate at which apartment builders are finishing projects. That means vacancy rates should continue to fall—and rents to rise—for the next year.