If you're digging for data, libraries (and Google) aren't the only place to go. Check out this fascinating look at New York City's Department of Records: New Yorker. They even have a visitor's center!
Here's another extraordinary place for New York legal research: the New York Legislative Service. Rather than combing through legislative history on your own, you can give these folks a call. They have folders filled with contemporaneous news stories, information from the governor, and classic legislative materials on thousands of New York state laws. They get a surprising number of requests from California attorneys because California's code was originally based on New York's. Legislative history that's good for the goose is good for the gander as well.