(Newser) – A public-minded mystery donor paid off a lot more than their share of the national debt with a record $2.2 million donation in September. Treasury officials haven't released any details on the source of the donation, which brought public contributions toward the debt to a total of almost $3.9 million for the last fiscal year, according to official figures. Contributions to the Public Debt Reduction Fund trickle in throughout the year, USA Today reports, though they amount to just a drop in a bucket big enough for King Kong to bathe in: The debt now stands at more than $18.6 trillion, and Forbes estimates that the interest alone grows by around $1 million per minute.

The debt donors in the first six months of the year included five Republican members of Congress and three Democrats who gave a total of almost $56,000, USA Today notes. The biggest giver, Rep. Chris Gibson, a New York Republican, hands over $4,357.37 every month. "He donates his military pension, so he is not—to use the term we use in New York—double-dipping," his press secretary says. "It's cumbersome. He has no choice but to write a check and deliver it manually every month." (After the latest debt ceiling deal came into effect, the debt surged by a record-setting amount in a single day.)

