Frequency: 16% of metropolitan areas in the OECD. Cities that exceed a legally defined population threshold can be upgraded into a special status as “metropolitan cities”, which puts them on the same footing as the next upper level of government and gives them broader competencies. Frequency: 8% of metropolitan areas in the OECD. Data from the OECD’s Metropolitan Governance Survey (2014) indicates that more than two-thirds of OECD metropolitan areas (178 out of 263, or 68%) currently have a metropolitan governance body (OECD, 2015).