inequality

My earlier answer touched on sources for making bubble charts, but I need to add more on how to get the data for those charts. A possible start might be the Census Bureau, which gets 4 hits for: inequality debt "time series" (use the tiny search box at upper right); and 15 hits for: inequality 1970s. You might do well to skim quickly through the list of about 150 for: inequality "time series", in case they might have many different words implying inequality.

You can also try search.usa.gov, which gets "about 322" hits for: Inequality debt "time series" 1970 2012. But note that this Bing search engine does a smart extract of what it finds most relevant - if you wait a minute or 2, that list drops to 35 or 36 hits. Compare a Google search for: Inequality debt "time series" 1970 2012 site:gov , which gets 168 hits. Note that Google's site:gov limiter will get different results than search.usa.gov - partly because that site includes STATE as well as federal sites and documents, including ones with the old URLs like ny.us, fl.us, ca.us, etc. In Google you can also limit to site:edu , which will get some free research reports, preprints, etc. - very different from the results in scholar.google.com, which is mostly commercial subscription journal articles, that .require you to be on campus at a subscribing university, or at least logging in via a student/staff password to their proxy server.

A possible start might be a Google search using site:edu, site:ac.uk, etc - to find unpublished or recent reports from university departments. For example, Google gets about 20 hits for: "bubble chart" inequality debt site:edu

You can also try site:gov, but first try the search: "bubble chart" inequality debt , in search.usa.gov, to find STATE as well as federal reports, documents, and web sites. I have no luck trying "bubble chart" inequality debt site:edu in Google images, but "bubble chart" inequality site:edu gets about 30. You can certainly try these searches in Google Scholar, without of course the site: edu, since Scholar IS all academic sources (at least we hope so!). But you would need to be onsite at a large university that subscribes to the many journals that Google Scholar indexes - or at least be going through a university's proxy server to get to Google Scholar.

If you are at a large academic library, you can also try commercial databases such as ScienceDirect, which defaults to full text search of all of its journals (all scholarly), and gets 3 hits for: Chart w/50 inequality w/50 debt. But authors often will not SAY if a chart is a bubble chart - you will probably have to look at a lot of charts or figures, to find a bubble chart that is not called a bubble chart. Also, that full text proximity search varies: Ebsco databases such as Business Source or Academic Search would require you to "select a field" TX-All text, and search: Chart n50 inequality n50 debt. JSTOR(default full text search) would say "chart inequality debt"~50. But JSTOR advanced search lets you select search of "caption", and that gets 7 hits for: inequality and debt. The thumbnail images don't appear to be bubble charts, but you may want to try looking in the full text PDFs, in case - or try different words.