It’s becoming increasingly difficult to find an affordable apartment in Portland. Landlord surveys have found that vacancy rates have dropped from 7.5 percent to roughly 2 percent over the last five years and the average monthly rent for a two-bedroom apartment has risen from $850 to $1,050 over the last four years. Harper Lee Collins, a Re/Max Realtor, tells The Portland Press Herald, demand for rental units increased as the housing market crashed in 2008, when people lost homes to foreclosures and lending for new buyers was tight. Rental agents report multiple qualified tenants interested in a single unit. The city has about 17,000 rental units and has made increasing housing options a priority. The plan for one development is 675 units over a 10-year period.