No doubt, the Twin Cities skyline is changing. That's because dozens of low-rise apartment buildings -- and a couple high-rise ones -- are now under construction. A new McGraw-Hill Construction report released this week says that the value of all permits issued to build those buildings during 2012 was up 63 percent in the 13-county metro compared with the previous year, rising from $1.6 billion in 2011 to $2.5 billion last year.

The value of non-residential projects (that includes streets, highways and bridges) actually fell 14 percent during the year; when combined, total construction spending was up 21 percent.

With demand for apartments still strong and sales of new houses on the rise, residential construction spending this year is expected to be even better than 2012.