Federal funding for research at higher education institutions declined for a fourth straight year, according to a new report from the National Center for Science and Engineering Statistics (NCSES).

During a peak in Fiscal Year (FY) 2011, federal funding accounted for 62.5 percent of total higher education research and development (R&D) expenditures. That figure dropped to 55.2 percent in FY 2015, the most recent year for which data are available. Overall, universities reported $68.8 billion in R&D expenditures for FY 2015; federal funding accounted for $37.9 billion of that.

Adjusted for inflation, federal funding for higher education R&D declined 1.7 percent between FY 2014 and FY 2015, and 13 percent since a peak in FY 2011. The latest figures continue the longest multi-year decline since the beginning of annual data collection in FY 1972.

Despite the drop in federal dollars, three agencies — the Department of Defense, NASA and the Department of Agriculture — reported increases. All other major providers reported decreases. That included the Department of Health and Human Services (HHS), by far the largest source of federal funds, which provided $20 billion in FY 2015, down from $23 billion in FY 2011.

While federal funds and funds from state governments decreased, other sources of university R&D funding saw increases. Universities’ own funding of R&D rose by 5.9 percent in FY 2015, business expenditures by 7.5 percent, nonprofit expenditures by 6.9 percent and expenditures funded by other sources (including donations and foreign sources) by 6.4 percent. Even with the federal decrease, overall university expenditures were up by 2.2 percent compared with the previous year.

Three fields — medical science ($21.3 billion), biological science ($11.7 billion) and engineering ($11.1 billion) — together accounted for 64.3 percent of total higher education R&D. Medical science showed modest growth between years, while biological science and engineering essentially remained level.

Among subfields, atmospheric science grew by 14.7 percent, to $576 million, and astronomy by 18.7 percent, to $673 million. Aeronautical and astronautical engineering increased by 10.9 percent, to $734 million.

For more information, including a list of the top 30 university performers of R&D, read the full report.