TheSE three maps show Portland's residential development over the past three years. Metro's Data Resource Center graciously built these snapshots using data provided by Construction Monitor. The small dots represent approved single-family home permits; the larger dots represent approved multi-family residential permits. All told, the four counties (Multnomah, Washington, Clackamas, and Clark in Washington) have added more than 9,000 residential homes or apartments since 2010.