Researchers at CoworkingCafe put together the top 20 U.S. cities with the highest number of coworking spaces in their central business districts (CBDs).

Key takeaways: Half of US coworking spaces in CBDs are concentrated in just five major cities: New York City, Chicago, Washington D.C., Los Angeles and Philadelphia. NYC leads the pack with 180 flex spaces across Midtown and the Financial District. Oakland, CA; Washington, D.C.; Philadelphia, PA and Chicago, IL have more than 2/3 of their coworking spaces concentrated in the CBDs. Houston, Austin, Dallas, TX and Denver, CO made the top 20 despite having more than 80% of their flex spaces outside the CBD.