I put a sample of a personal net worth statement template form up on Google Docs. You can easily download it then add and remove rows at your leisure. Keeping a local copy you can add and remove accounts as needed without re-creating it every time.
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.