If something is taken for granted, it's a given. You can count on it. In fact, you are already counting on it. Most Americans take for granted the right to vote.
Granted as an adjective means "given," and it usually follows "take for" or "taken for." If you take someone for granted, you count on that person but you may not always show your appreciation. If someone accuses you for "taking them for granted," you should respond negatively and say something like: "Oh, no I don't. I thank my lucky stars for you every day!"