U.S. Census Bureau: In the Past 43 Years, The Percentage of One-Member Households Has Increased From 17% in 1970 to 27% of Total U.S. Households in 2013.

The U.S. Census Bureau report is linked below.

U.S. Census Bureau: One-Member Households On the Rise Over the Past 4 Decades

"The proportion of one-person households increased by 10 percentage points between 1970 and 2013, from 17 percent to 27 percent."

---U.S. Census Bureau, November 25, 2013 Report