The biennial guide to the state of the sector reveals that, despite large numbers of much-vaunted corporate responsibility policies, the private sector's contribution barely registers.
The figures, taken from 2003/04 charity accounts, show a sharp drop in company giving since 2001/02, when it stood at 4 per cent.
The true level of corporate generosity is also vastly at odds with public perceptions - an opinion poll from 2004 shows the public believes that 24 per cent of charity income is derived from the corporate sector. And corporate giving has dropped in real terms as well as relative to other sources of income.
"Yet again we have seen income from businesses fall," said Campbell Robb, director of public policy at the NCVO. "The private sector talks a lot about corporate responsibility, but there is much more to be done in this area, and it is clearly time to start turning this rhetoric into reality."
The state continues to be the largest single provider of charity funds - it gives 38 per cent of total income, up from 37 per cent in 2002. Fees have now overtaken grants as the most common form of state funding. Giving by individuals has dropped slightly, from 37 per cent to 35 per cent.
Money from foundations and trusts now contributes 10 per cent of the total, up from 7 per cent two years ago.
Some 169,000 charities are now registered, a net increase of 28,000 since 2000.
Susan Wainwright, research officer at the NCVO, said the sector had been swelled by the creation of new grant-making foundations and the reclassification of local authority leisure services as charitable trusts.