As this letter on the site ReinventAlbany - Group Letter to NYC Corporate Counsel states, you should request information in machine-readable format, and if it exists in that format, the agency must provide it in machine-readable format, and not in pdf format:
"Currently, many city agencies respond to FOIL requests by converting machine readable tabular data, like MS Excel spreadsheets, into PDF files, which are not machine readable. This has the practical effect of making these records much more difficult for the public to use. City agencies often produce records that include dozens or hundreds of pages of tabular data. When this data is locked in a PDF format, public interest groups, advocates and others must spend extraordinary time and expense to retrieve information that would take a moment to find if the data was machine readable. This is contrary to the Freedom of Information Law, which seeks to “free” information, not make it difficult for the public to use."
"The New York State Committee on Open Government, which oversees and interprets the Freedom of Information Law, explains: “If an agency has reasonable means to convert accessible records from one electronic format into a different more desirable format, it must do so.” (New York State Committee on Open Government web site, citing N.Y. Pub. Officers Law §§ 87(a) & 89(3)(a))"