It is remarkably difficult to get digitized Census data files at the tract level from before 2000.
County-level data is available at the Census Publications Library, in PDF format; and you can also get County Subdivision data from these records back to at least 1960. I have compiled tables of whole-county data for selected California Counties back to 1960. In each case there are some shortcomings:
1990 California Counties data includes categories close to the groupings used in the 2010 Census.
However, Asian and Asian Pacific Islander data is not separated. Please read the notes at the top of the document.
1980 California Counties data: see the bottom of this page.
1970 California Counties data: not only are Asians and Pacific Islanders treated as a single category, but Hispanics are not differentiated at all. People of Spanish origin are counted at the County level, but that count overlaps with race counts.
1960 California Counties data: Asians and APIs are aggregated together, and there is no mention of Hispanic/Latino at all.
For the 1990 Census, Public Law 94 (electoral redistricting) funded the digitization of tract level data by race. This is the link to the 1990 Census Data.
In class I showed how to get this data:
1) “scrape” the data displayed in table format on the Census website,
2) paste it into a word-processor, which should recognize that it is a table;
3) select the whole table in your word document, and copy it;
4) paste the data into a spreadsheet.
For some reason, it is hard to copy the data straight off a webpage and paste it directly into a spreadsheet. I suspect the problem is that word-processors have tolerant, heterodox import-functions, whereas spreadsheets are much more strict.
1980 Census Data
Chris Bettinger pointed me toward historic California Census data, and I downloaded a 100 MB archive to discover that the data is just PDF-scans–essentially photocopies of the original books in non-readable image-scan format. Furthermore, the table-structure is utterly different from more recent Census data. So I took most of today to restructure the data into a format similar to the 2010 Census:
|San Luis Obispo||155435||132809||2649||14792||1726||2650||0||80|
Source for Total and Latino: Table 44: “General Characteristics for Counties and County Subdivisions: 1980.”
Source for non-Latino White & Black: Table 51, “General Characteristics of Persons by Type Spanish Origin for Counties.”
Source for AIAN, Asian, and NHPI: Table 50: “General Characteristics, Selected Racial Groups for Counties: 1980.”
NOTE 1: American Indian and Aleut are added together to comprise AIAN.
NOTE 2: East-, Southeast-, and South Asian groups added together to comprise Asian.
NOTE 3: Hawaiian, Guamanian, and Samoan added together to comprise NHPI.
You can scrape the data (or hand-copy it) off this page, or download a CSV version posted here.