The percentage of households headed by single parents showed little variation from 1994 through 2006, at about 9 percent, up from 5 percent in 1970. There were 12.9 million one-parent families in 2006 — 10.4 million single-mother families and 2.5 million single-father families. Just over two-thirds (67 percent) of the nation's 73.7 million children younger than 18 lived with two married parents in 2006. Also in 2006, there were an estimated 5.8 million stay-at-home parents: 5.6 million mothers and 159,000 fathers.
U.S. Census Bureau
Single-Parent Households Showed Little Variation Since 1994, Census Bureau Reports