Assessment percentage?

How would we know? Ask your managing agent.

Assessments in a co-op are per share, so they must've meant percentage of maintenance. That was an odd way for the accountant to express it; usually it's something like "$x per share."

It could be a condo, the OP didn't mention whether it was a condo or co-op. The co-op typically mentions $ per share. I am treasurer for my condo and I expressed assessments by percentage of common interest.

thx for the replies, its a coop.

are assessments usually a lump sum, or monthly for a year (or longer duration)?

They're almost always spread over however many months. E.g., if a new roof is planned for Summer 2014, you'd assess over 18 or 24 months, beginning January 2013, to get the money together.

A big-bucks building might just let you know six months ahead of time about a upcoming lump-sum assessment.

A small building might not have the reserves of a large building, and it could easily be a lump sum assessment or spread out over a much shorter horizon than NWT suggested- i.e. 3 months. Typically though in mid-large sized buildings they will assess over long periods as NWT noted.

In summary- there is no standard, every building has different needs and different time horizons.