Components of change in the number of households: 1970-1980.

There was an increase from 62.8 to 79.1 million households in the United States during the 1970s. The number of households increased much more rapidly than the population. This paper decomposes this growth in the number of households into components associated with changing age and martial status composition and changing age by marital status-specific propensities to form households. About one-third of the increase in the number of households was due to increased age by marital status propensity to form households, and two-thirds was due to shifts in the age by marital status distribution and population growth. The increased propensity to form households had its major impact at ages under 35, and primarily among never-married persons. The composition component had its primary impact at ages 25-44 as a result of the baby boom, and also because of the increased fractions never married and separated and divorced.