The number of younger Americans who are choosing not to wed has reached record levels, according to figures from the Institute for Family Studies (IFS).

Data shows that over a third (35%) of American adults between the ages of 25 and 50 have never been married - a proportion that amounts to 39 million people.

It represents a dramatic decline since 1970, when the never-marrieds accounted for only 9% in that age group.

But the turn away from marriage in this age group has accelerated in recent years, rising from just a fifth (21%) in 2000 to 35% today.

The IFS analysis found that lower income Americans were more likely to reject marriage.

In 2018, 42% of never-marrieds were classed as lower-income - earning below $20,000, compared to less than a quarter (23%) who were earning over $50,000.

This is a significant change from 1970, when there was little difference in the rate of lower income and higher income younger Americans choosing not to marry.

"This stark contrast in marriage formation across income lines may further widen the income gap and affect income mobility," wrote IFS author report Wendy Wang.

"Marriage is about love and commitment, but it also offers economic benefits to couples. When couples live under one roof and pool incomes, this can be a significant saving in living expenses."