This is being attributed to demographic shifts in marital status, employment and educational attainment.
Marital status
Young adults living with their parents is being fueled primarily by the dramatic drop in the percentage who are choosing to settle down before age 35.
A growing percentage of young adults are eschewing marriage. Projections say that as many as 25% of today's young adults may never marry. While cohabitation has been on the rise, the overall share of young adults either married or living with an unmarried partner has fallen substantially since 1990. The current average age of marriage is 27.1 for women and 29.2 for men.
Employment
Employment among young men has fallen significantly in recent years. In 2014, only 71% of 18-to-34 young men were employed. Earnings among young men have also been declining. This can be attributed to the Great Recession. Living at home has become a safety net to help weather the economic storm. Young women have not been affected as much in this area with continuing gains in employment.
Educational Attainment
36% of young adults who have not completed a bachelor's degree are living with their parents. For those who did not complete high school, 40% live with their parents.