{ "currentVersion": 10.91, "cimVersion": "2.9.0", "serviceDescription": "US Census Block Group areas use boundaries from the most recent census and population estimates for the current year. A Census Block Group is a geographical unit used by the U.S. Census Bureau to summarize population statistics. It is comprised of several Census Blocks. A Block Group is also a sub-unit of the larger Census Tract. Block Groups generally contain between 600 and 3,000 people.\u200b