The BJP got Rs 461 crore as donations from 'unknown sources' in 2015-16, accounting for nearly 81 per cent of its total income, while the same for the Congress was 71 per cent or Rs 186 crore, a report said today.

Citing their tax returns, the report by the Association for Democratic Reforms (ADR) said the two parties together got Rs 646.82 crore, or over 77 per cent, of their total income from "unknown sources" during the year.

Income from "unknown sources" refers to those where the source is not declared for donations below Rs 20,000. Such income includes those from sale of coupons, relief fund, miscellaneous income, voluntary contributions and contribution from meetings or morchas, stated the report.

The details of donors of such voluntary contributions are not available in the public domain, it said.