The average household contains 2.54 people for 2017. Remember that households also includes things like roommates, cohabiting couples, and adult children living in the basement. The idea of an average household having 2 parents and several kids ended around 1973 [0], assuming that back when households had around an average of 3 occupants it was due to the so called "atomic family."

0: https://www.statista.com/statistics/183648/average-size-of-h...