A REPORT by the Institute for Fiscal Studies finds no evidence that the advent of the National Lottery has had a significant impact on charitable giving. But charities are nevertheless experiencing a long term decline in the number of donors, especially among younger households. Whilst 34% of households donated to charity in 1974, the figure had declined to 30% by 1996. However, the average value of donations has risen to £4.11 weekly, due largely to more generous giving by middle-aged households. The study, The State of Donation, is based on family expenditure survey data from 150,000 households and is available for £10 from the IFS, (0171-636 3784).