The U.S. Census Bureau news release is linked below.
Approximately 1 Million Korean Speakers in U.S. Homes in 2011
"A U.S. Census Bureau report released [ September 11, 2013 ] says that there were 1.1 million people who spoke Korean at home in 2011. Korean was one of eight languages spoken by at least 1 million people."
---U.S. Census Bureau News Release