Calculated Risk has posted an interesting graph by economist Tom Lawler comparing the proportion of 24-34 year olds living at home to the under 35 year old homeownership rate, commenting that, ". . . There is a clear inverse relationship, and this suggests some pent up demand for housing units when the employment picture improves (although the demand could be for rental units)."
Sources: ASEC March Supplement to Current Population Survey for % living with parents (note sample size, other aspects of survey not constant over time); Housing Vacancy Survey for homeownership rate (note HVS homeownership rate has exceeded Decennial Census AND American Community Survey estimates)