The number of vacant apartments in Lawrence is at its highest level since 1997, according to a recently released study.

Nearly 8 percent of the city’s apartments in 2003 were unoccupied, according to a survey conducted by Lawrence-based Keller & Associates, a real estate appraisal firm. That’s up from 6 percent in 2001, the last time the study was conducted. The 2003 number was slightly lower than the 10 percent mark posted in 1997, which was one year after the city’s largest apartment building boom. There were 842 units built in 1996.

Tim Keller, of Keller & Associates, said the economy had played a factor in reducing demand.

“Some tenants are electing to economize by rooming with more tenants,” Keller said in an e-mail.

Keller also attributed the rise in vacancy rates to lower interest rates. Tenants have become homeowners, Keller said.

The study’s findings came as no surprise to area apartment managers.

Linda Love, manager of Park-25 Apartments, 2401 W. 25th St., is experiencing a 12 percent vacancy rate. The 30-year-old 254 unit complex at this time of year typically has a vacancy rate of 2 percent or less.

Love said the Lawrence apartment market was saturated.

Despite lower occupancy levels, Keller is not concerned.

“The Lawrence apartment market remains healthy relative to other apartment markets and other commercial property types in Lawrence,” Keller said.

He is optimistic that the occupancy rates will improve.

In the meantime, apartment managers are having to make changes to adapt to the tight market. Park-25 began allowing pets in its apartments three years ago.

“We have to re-evaluate how we do our job, all the way from the ground up,” Love said.

Keller’s survey measured the vacancy rate as of Aug. 31. The survey reflects data contributed by property owners and managers of almost 3,000 units, or about 35 percent of the total market.