For the fourth time in the last five years, donations to athletic departments nationwide raised more than $1 billion, according to a report by the Council for Aid to Education.

On Wednesday, The Chronicle of Higher Education published an article looking a bit more closely at the top 10 fundraisers in 2015, which feature two Pac-12 schools. It should be noted that the survey was voluntary, and some schools (including LSU, Florida State and Clemson) chose not to participate, but nearly 400 institutions did take part.

Among the schools that did, Oregon raised the second-most in private donations, nearly $54 million. The Ducks finished second to Texas A&M, which raised a whopping $67 million. Washington finished with the eighth-most in 2015, nearly $31 million.

Overall, some $1.2 billion was raised by the reporting schools, a slight decrease from what the 2014 cycle raised, but the growth over the long term has been astonishing, The Chronicle found -- in 2005 just five schools reported donations exceeding $20 million; in 2015, 25 schools did.

Unexpectedly, the richest athletic departments were also the ones that raised the most in donations. The top 20 athletic departments collected $670 million of donations, more than half of all the programs' totals.

"But there are signs that donors may be reaching their limits, as overall athletics donations to the reporting institutions dipped slightly in 2015 from the year before," The Chronicle's Brad Wolverton and Sandhya Kambhampati wrote. "A drop in the stock market contributed to that decline, athletics leaders say. So did donor fatigue, with some supporters questioning programs' efforts to raise donation requirements for tickets and to seek money for increased compensation for coaches."

With the trend of breaking $1 billion at four of the past five years, all signs point to 2016 continuing to see big donations, but only time will tell if donors have reached critical mass or not.