Stay at home dads still barely register

There are not many fathers in the U.S. who are choosing to be stay at home dads. If you look at the graph below you'll see that the number of married couples with children under the age of 15 has declined over the past 18 years; the number of stay at home mums has increased slightly; and that the number of stay at home dads (the green line) has risen but is still negligible.

It seems unlikely at this point that a role reversal family with a breadwinning mother and a stay at  home father will challenge the traditional family.