Factor in the devaluation of the dollar and its about the same. Regarding the family in regards to inflation, it has little to do with the traditional family. Other factors effecting the great decline in marriage is the Soviet originated concept of 'no-fault' divorce implemented in the US in 1961. From that time on, the growth of divorce grew exponentially.

From the chart, one can see perhaps an indication of the effect of divorce on the children who now as adults increasingly prefer to live with an unmarried partner. The other factor that has risen considerable from the 1970s is living with parents/other relatives. I don't believe the economy is a significant factor in this, rather it may stem from radical sexual ideology as a result of institutionalized indoctrination and propaganda. Also, Americans are predominantly obese. The ratio may be in the neighborhood of 3 out of 4 Americans being obese. The obesity problem causes mental health issues. This would certainly be a factor for living with the parents.