As you can see from the Household Net Worth Statistics charts below, the median value of household net worth for families has risen rapidly since 1989.
Here are the latest statistics available for average (mean) U.S. Net Worth Distribution Statistics by Age. You can see the trend over time in the first chart and view the raw numbers in the bottom chart.
I was looking for Rich-O-Meter 3.0 and here is what I found as a followup to my original post on net worth percentiles and the Rich-O-Meter.
Here are the latest Net Worth Wealth Percentiles available using 2013 data. Net worth is the difference between assets and liabilities. Therefore if debt is higher than total assets, net worth can be less than zero as you see in the first percentile bracket for mean net worth.