Plus, the City Council is considering implementing a vacancy tax on property owners who fail to find tenants in hopes it would offset the county tax relief some receive for having vacant properties — something politicians have attempted to address in the past. He presented updated numbers to City Council in July — attributed to real estate data provider CoStar — which showed the downtown vacancy rate dropped to 5.6% for retail vacancies but rose to 18.7% from 18.5% in the same period for office vacancies. A proposed vacancy registry in Mobile, Alabama would set several fee structures for vacant properties listed on the registry that address both commercial and residential properties, for example.