Data Table
Explanation
The composition of the family has changed drastically over the last 40 years. In 1970, married couple families constituted 72% of all households; by 2015-2019 this dropped to just 52%.
While the number of married couple households has decreased during this same period, one-person and non-family households have increased (from 20% to 34% of all families). Single-parent families also grew over the period. For 2015-2019, Yelm had the highest percentage of married couple households (63%) while the Chehalis Reservation had the lowest (27%).
Source
U.S. Census Bureau