I used to own on East 36th bet 2nd and 3rd - LOVE MURRAY HILL it's a nice quiet understand area with not much outsider intrusion. I would say young to middle age professionals and lots of single people who are heterosexual 30's to late 40's in age I would surmize.
That's a question that Real Estate professionals are not inclined to answer, nor are we allowed to answer by law. The best way to know about a particular building or neighborhood is to check it out yourself. You'll enjoy the experience, especially as the weather gets warmer and Springs hops into gear. Good luck!
I looked up the building and noticed that it has a full-time doorman. Your best bet to get information like that about a particular building would be the doorman. Real estate agents normally steer clear of answering those types of questions.