How to use System Font with an Attributed String?

let attributedText: NSMutableAttributedString = NSMutableAttributedString(string: text, attributes: [NSFontAttributeName: UIFont(name: "San Francisco", size: 14.0)!])

Using the code above, when I run my app it crashes because it cannot find the "San Francisco" font. But isn't that the system font for iOS 9? How can I use the system font in an attributed string?

I am using Swift 2.2