For the last 10 years, the number of millennials who have failed to move out of their parents or grandparents homes has climbed steadily, according to new data.

Nearly 40 per cent of young adults are either living with their parents or other relatives, which is the highest point in over seven decades, new data from real estate analytics company Trulia states.

This is the highest point in 75 years where young adults have just stayed at home with no plans on moving out.

The only other time in American history where the share has been higher was back in 1940, when the economy was recovering from the Great Depression.

For the last 10 years, the number of millennials who have failed to move out of their parents or grandparents homes has climbed steadily (file photo)

This current trend of millennials who are still living at home apparently started shortly before the Great Recession of 2008.

However, it accelerated quickly during the downturn and recovery.

The occurrence is seemingly related to several factors, including economic headwinds, Americans delaying marriage and society shifts, CBS News reported.

Another issues is the fact of low wage paying jobs, increased rent and student loan debt.

'Even though unemployment rates have decreased and the economy is picking up, we know wages are stagnant, so this will impact this generation of home buyers,' Cheryl Young, senior economist at Trulia told CBS News.

'The millennials are getting married later and having fewer children, and that's particular to this generation.'

Earlier this year, the Pew Research Center found that 32.1 per cent of 18-to 34-year-olds lived with their parents in 2014.

That percentage exceeded the 31.6 per cent of young adults who lived with a partner or were married in their own household.

'For most people who take the traditional trajectory, you might rent, then you are ready to buy a home,' Young said.

This is the highest point in 75 years where young adults have just stayed at home with no plans on moving out or buying their own place (file photo)

'But if people are living with relatives, it means they aren't even able to rent.

'The rental prices are very high in some urban areas, and those are barriers for people to move out.'

According to Pew, millennials are making less money than Generation X.

In 2014, millennial households earned a median income of $61,003 compared with the inflation-adjusted $63,365 for those in Generation X in 1998.

According to Harvard’s Joint Center for Housing Studies, home ownership rates for Americans in their 20s and 30s have decreased significantly, and will likely worsen as millennials who have deferred their loan repayments will have to start paying on the huge debts since grace periods are coming to an end.