Even after hue and cry about corruption and the presence of black money circulating in the Indian economy, political parties are not ready to walk the talk on transparency, as a major share of their source of income remains unknown.

As per the data revealed by the Association for Democratic Reforms (ADR), 69% or Rs 7,832 crore of the total income of six national and 51 regional parties from 2004-2005 to 2014-2015 came from unknown sources. The current rules allow parties to keep confidential the source of the donor, if the amount is less than Rs 20,000.

Of the total number of parties, from whom data was received, three national and three regional parties contested the assembly elections in Goa. The figures reveal Congress as the biggest earner, with its total income standing at Rs 3,982.09 crore, followed by Bharatiya Janata Party, whose earnings add up to Rs 3,272.63 crore. Nationalist Congress Party has the fifth highest income at Rs 351 crore, during the 11-year period.

The data, which has been compiled by information taken from the statements submitted by the political parties to income tax department and Election Commission of India, shows that over two-thirds of the funds cannot be traced and are from 'unknown' sources.

"The unknown sources are income declared in the I-T returns, but without giving source of income for donations below Rs 20,000. Such unknown sources include 'sale of coupons', 'Aajiwan Sahayog Nidhi', 'relief fund', 'miscellaneous income', 'voluntary contributions', 'contribution from meetings/ morchas' etc. The details of donors of such voluntary contributions are not available in the public domain," the ADR report states.

Among the regional parties contesting the state assembly polls, Shiv Sena declared the second highest donations of Rs 49.07 crore, while AAP has declared the third highest donations amounting to Rs 45.46 crore. Maharashtrawadi Gomantak Party(MGP) earned an income of Rs 2.20 crore, out of which only Rs 0.16 crore accounts from known sources.