The composition of the family has changed drastically over the last 40 years. In 1970, married couples constituted 72% of all households; by 2018 this dropped to just 51%.
While married couple households has decreased during this same period, one-person and non-family households have increased (from 20% to 33% of all families). Single-parent families also grew over the period. In 2018, Yelm had the highest percentage of married couple households (57%) while Olympia had the lowest (37%).