(Bloomberg Business) — For all the talk of shifting gender dynamics within the American nuclear family, surprisingly little has changed when it comes to who brings home the bacon. 

For one: The share of married heterosexual couples with children under 18 in which the mother is the sole breadwinner declined in 2014 for a fourth year to 5.6 percent, almost completely erasing the jump made in the recession, according to a recent Bureau of Labor Statistics report. It marked the steepest decline in data going back to 1994. The rate is now only 0.3 percentage point away from its two-decade average, represented by the horizontal line in the chart below. 

In the meantime, the share of dual-earning couples is actually lower than it was in 1994. The measure inched up last year to 60.2 percent, recovering some ground since stumbling to its 2010 low. Still, it's more than a percentage point below the 21-year average.