A Federal Reserve’s 2004 Survey says:
The numbers are per family, which is similar to household used by the census bureau.
Age 35 - 44
median net worth $69,400
mean net worth $299,200
Age 45 - 54
median net worth $144,700
mean net worth $542,700
Age 55 - 64
median net worth $248,700
mean net worth $843,800