This report from the Kaiser Family Foundation examines Medicaid enrollment data, finding that enrollment increased by 3.7 million individuals between June 2009 and June 2010. KFF also notes that Medicaid enrollment grew by 7.6 million individuals, or 17.8 percent, since the recession began in December 2007

From the report: 

Medicaid enrollment increased nationwide by 7.2 percent, or 3.37 million, between June 2009 and June 2010, exceeding 50 million enrollees for the first time in the program’s history (Figure 1). Medicaid enrollment has grown by 7.6 million (17.8 percent) since the start of the recession in December 2007. Between that month and June 2010, the nation’s unemployment rate nearly doubled from 5.0 percent to 9.5 percent. Many Americans lost jobs, incomes, and access to affordable employer coverage. Consequently, demand for Medicaid grew. Medicaid enrollment hit a record high of 50.3 million in June 2010. Millions more who did not qualify under their state’s existing Medicaid eligibility criteria likely joined the ranks of America’s now 50 million uninsured.

Full Report: Medicaid Enrollment: June 2010 Data Snapshot (PDF | 495 MB)  

Kaiser Family Foundation. (2011). Medicaid enrollment: June 2010 data snapshot.