Forget Ask.com. If you have a question about American graduate education over the last 100 years, you can probably find the answer in a data-heavy report released this week by the National Science Foundation.

The report, "U.S. Doctorates in the 20th Century," contains an almost mind-numbing array of statistics about who received Ph.D.'s, what fields the degrees were in, the institutional paths the recipients took to their doctorates, and how they paid for their educations, among other topics. Generally, the report lays out a history of remarkable growth and, particularly of late, changing demographics.

Among the report's findings:

• Of the more than 1.35 million doctorates awarded by universities in the United States between 1920 and 1999, 62 percent were in science and engineering fields -- but more were given out in education than in any other single discipline in every year from 1962 on.
• Although men received 73 percent of the doctorates throughout the century, the proportion earned by women rose from 15 percent in the early 1920s to 41 percent by century's end. Among other demographic changes: The proportion of Ph.D.s earned by members of minority groups rose to 14 percent in the period from 1995-99, up from 6 percent in 1975-79. And foreign nationals earned almost one of every three doctorates granted by American universities by the late 1990s, up from one in four just a decade earlier.
• Fifty baccalaureate institutions produced more than a third of the people who went on to earn doctorates between 1920 and 1999. Of those 50 institutions, Oberlin College was the only one that does not itself award doctorates. (Oberlin ranked 35th.) Community colleges played an increasing role in the doctoral pipeline, the report found: More than 11 percent of all U.S. citizens awarded doctorates in 1995–99 had attended two-year colleges, up from about 10 percent in the late 1970s. But the overall proportion of doctorate earners who had attended a community college actually fell to 8 percent from 9 percent, seemingly because of the significant increase in the number of foreigners in the pool of doctorate earners.
• Ph.D. recipients have increasingly had to go into debt to earn their degrees. By 1999, for the first time, more than 50 percent of graduating doctorate earners had accumulated education debt, and the proportion who said they owed more than $20,000 had climbed to 20 percent, up from less than 7 percent a decade earlier.
• That finding may be related to another striking result: The median time it took to complete a Ph.D. (after receipt of a bachelor's degree) increased from 7 years in 1920-24 to almost 11 years in 1995-99.