The percentage of taxpayers who submit income returns under the self-assessment system has been falling steadily, figures contained in the Comptroller's report show. Up to May 31st, 1997, 84 per cent of those on self-assessment had submitted income tax returns for the year ended April 5th (1995/'96). This compares to 91 per cent for the previous tax year and 96 per cent for 1993/ '94. Similarly, corporation tax returns have been slipping. In 1995, the rate was 74 per cent. This compares to 79 per cent in 1994 and 82 per cent in 1993.