Today's chart, sourced from Apollo and the Census Bureau data, illustrates a decline in the average family size from 3.3 members per household in 1960 to 2.5 in 2023. The trend began in 1965, with many attributing it to the enactment of the Social Security Act as part of Lyndon Johnson's "Great Society" program, which expanded benefits enabling older parents to live independently from their adult children. While the decline is stabilizing, recent decreases are primarily attributed to families having fewer children.