Population counters added 7.3 million people to the 1990 census based on secondhand information from neighbors, postal carriers and building superintendents, congressional investigators say.

But the counters went to secondary sources only after six unsuccessful attempts to interview members of a household, Barbara Everitt Bryant, the census director, told the House census and population subcommittee on Thursday.L. Nye Stevens of the General Accounting Office said hearsay information was most common in urban areas. The practice "introduces a potential source of error into the census," Stevens testified.

The Census Bureau's self-described "last-resort methods" were among many attempts to count everyone in the nation. Hearsay numbers account for about 2.9 percent of the census total of 248.7 million.

The Census Bureau is reviewing that and other counting methods and will determine by midsummer if the numbers need to be adjusted.

Bryant gave this breakdown of where the census numbers came from:

-Mail-in census forms: 166.9 million.

-Counts by census takers: 10.9 million.

-Counts of the homeless, the transient and others in group quarters: 6.6 million.

-Follow-up calls by census takers: 58.8 million.

That initial count of 243.2 million was 97.8 percent of the final U.S. resident population figure, Bryant said. The bureau added 2.2 percent by rechecking housing thought vacant, asking people to come forward if they were missed, checking lists of parolees and probationers and following leads passed on by local governments.

Meanwhile, New York officials on Thursday questioned the accuracy of census breakdowns showing the number of Hispanics increased more than 33 percent and the number of Asian and Pacific residents more than doubled across the state in the 1980s.