The Housing and Vacancy Survey, based on a sample of 19,000 selected residences across the city, is the city's official determination of the vacancy rate.

According to the Housing and Vacancy Survey, the number of vacant apartments in the city rose from 70,345 in 1993 to 81,256 last year.

Data for the study were taken from the 1996 New York City Housing and Vacancy Survey, which sampled 15,752 households, 5,933 of them headed by immigrants.

The results are based on data from the city's official 1996 Housing and Vacancy Survey.

The study breaks down its figures by sections of boroughs taken from the Housing and Vacancy Survey.

According to the Housing and Vacancy Survey, in 1991 the median income for the community was $17,000; in 1999 it was $24,000.

Given recently released data from the city's 1999 Housing and Vacancy Survey, he said, "one might be surprised by the rapid increase in prices over the past few years."

In 1993, however, the city's Housing and Vacancy Survey indicated that less than 2 percent of all apartments with rents below $500 were vacant.

According to the 1996 New York City Housing and Vacancy Survey, 61.7 percent of the rental buildings in the city have fewer than 50 apartments.

According to the 1999 New York City Housing and Vacancy Survey, 24.3 percent of all renters pay more than half their incomes in rent.