I was poking around the Census site and discovered another historical income series: median income by number of earners in the family. What caught my attention was that around the late 60s/early 70s the income for a single earner family flattens while the other income series (from no earner to 4 earner families) continue to grow. I copied the data used in this graph into a Google spreadsheet Family Income by Earners. It can be viewed by anyone with a Google Account.
