The participants on today's call will be Terry Considine, our Chairman and CEO, who will provide opening remarks; Keith Kimmel, Executive Vice President, in charge of Property Operations; and Ernie Freedman, our CFO, will review second quarter results and 2012 guidance. Also in the room today are John Bezzant, Executive Vice President, Transactions; Miles Cortez, EVP and Chief Administrative Officer; and Dan Matula, EVP of Redevelopment and Construction Services. We are available to answer questions at the conclusion of our prepared remarks.
I will now turn the call over to Terry Considine. Terry?
Thank you, Lisa, and good afternoon to all of you on this call. Thank you for your interest in Aimco. Business is good. During the recently completed second quarter, Aimco continued on plan. During the second quarter, we earned FFO of $0.46 per share. That's up 10% year-over-year. And we earned AFFO of $0.34 per share, that's up 17% year-over-year.
The operating team led by Keith maintained high occupancy while increasing rents, with new and renewal rents averaging 5% higher than rents on expiring leases.
The 12-month leases, the hard work of Keith and his team walks in today a revenue base supporting the growth we expect over the next year. Keith's team also excelled in cost discipline, particularly in the area of labor utilization, as you can see in the 8% year-over-year decline in payroll costs. Importantly, we maintained a healthy level of capital investment and maintenance spending. Our properties are in good condition, as you can see from the rising rents they command. Our portfolio gets better and better. Its average revenue per unit was about $1,300 in the second quarter. This important measure of portfolio quality determined and paid by customers was up about 8% year-over-year, about 1/2 due to rent growth and 1/2 due to acquisition and redevelopment of higher rent properties funded by the sale of lower rated properties. Cash from the sale of lower rated properties was used to fund redevelopment activity and 3 property acquisitions. Average monthly revenue per unit for the properties sold year-to-date was about $740. Average monthly revenue per unit for our 3 acquisitions year-to-date is about $1,400, almost twice. And average un-trended monthly revenue per unit for year-to-date redevelopment starts is expected to be about $2,100, or nearly 3x the rate of the properties sold. As I said, our portfolio gets better and better.