Federal spending on scientific research at universities and colleges rose slightly in 2008, following two years of declines, but the federal share of total academic research spending again dropped, according to figures released on Thursday by the National Science Foundation.

Over all, higher-education institutions reported research-and-development expenditures of $51.9-billion in the 2008 fiscal year, 2.3 percent more than the previous year in inflation-adjusted dollars, the NSF said in a summary of the findings of its latest “Survey of Research and Development Expenditures at Universities and Colleges.” The federal government remained the largest source of such funds, providing $31.2-billion in 2008, up from $30.5-billion in 2007. But the figures show a continuing erosion in the federal share of total spending, from 64 percent in 2005 to 60 percent last year.

Institutions increased their own spending on research by 7 percent, to $10.4-billion last year, and contributions by industry to academic research were also up by about 7 percent, to $2.9-billion. Spending by state and local governments rose by almost 9 percent, to $3.4-billion.

The NSF survey includes data from 690 colleges and universities that grant degrees in science or engineering and that reported spending at least $150,000 on research and development in those areas.

The top 20 institutions reporting the largest total expenditures accounted for 30 percent of total research spending, according to the report. The Johns Hopkins University again was by far the leader in research spending, with its $1.7-billion total including $845-million in spending by its Applied Physics Laboratory.

The NSF also released a ranking of institutions by the amount of federal funds received. The table below shows the top 100 institutions on that list, with the amounts received in 2008 and 2007.