Americans are in no hurry to file their 1990 tax returns.

Through Feb. 8, the Internal Revenue Service had received returns from 15.7 million couples and individuals, down 8.1 percent from the nearly 17.1 million tallied during the same period last year.The later filing continues a trend that the IRS has noted for several years.

The IRS said last week that it had processed nearly 6.6 million returns, down 3.1 percent from the 6.8 million during the period a year earlier.

The number of returns qualifying for refunds also dropped slightly, from 2.18 million last year to 2.05 million. However, the average refund rose to $963, compared with $871 at this time last year.

Electronic filing is considerably more popular than a year ago. More than 2.6 million returns have been filed electronically, more than double the 1.27 million at this time in 1990.

The IRS promises refunds in a maximum of three weeks for electronic returns, and even more quickly if the refund is deposited automatically in the taxpayer's bank account. Paper returns filed this early in the year can take up to six weeks to produce a refund.

Electronic returns are filed by computer through thousands of offices authorized by the IRS. In addition to promising quicker refunds, the IRS says electronic returns reduce mistakes.