Four months after Sandy, downtown Manhattan has largely recovered, according to a study from the Downtown Alliance.

It finds 99 percent of commercial office space and residential space has been reopened. Most hotels are operating again too.

But City Council Speaker Christine Quinn said many people are unaware that most services have returned.

"I am worried - I'll be honest - that there is a perception out there, that Lower Manhattan is not open, that businesses are not back in their headquarters," Quinn said, at a breakfast Thursday hosted by the Downtown Alliance, a business group.

One weak point, according to the study, is retail. Ten percent of stores remain closed due to physical damage, or communications problems, resulting from Sandy.

The South Street Seaport was particularly hard-hit by the storm and is still struggling to get back to pre-storm levels.