The rate of increase of journal prices over the last 10 years has far outstripped overall inflation. The result is, for instance, that “a large academic library which subscribed to a broad range of journals and whose acquisitions budget has increased between [year] and [year 12 years later] at the general rate of inflation would be able to purchse only 62% of the journals it could have purchased 12 years earlier.”
Answer: the years are 1967 and 1979.
Source: Wood, D. N. (1983). Reprography and copyright with particular reference to inter-library lending activities—a view from the BLLD. Aslib Proceedings, 35, 457-467.