why UIScrollView is leaving space from top in ios 6 and ios 7

I have turned off Autolayout and viewcontroller is embedded in navigation controller. I am using Xcode 5, Storyboard.

I don't understand why is it leaving space from top. Actually in storyboard i have put my label exactly below navigation bar. But when i run it on simulator then it leaves space from top.

One of the hacky way to resolve this

-(void)viewWillLayoutSubviews
{
   self.scrollViewMain.frame = CGRectMake(0, -70, 320, 800);

   self.scrollViewMain.contentSize = CGSizeMake(320, 800);
}

But am i missing something very simple approach.

In Xcode 5, in storyboard select your controller > in Attribute Inspector disable Adjust Scroll View Insets Also check if you have set any contentInset

Edit : I attached a pic

The fix is to implement the following line of code after in the viewDidLoad;

self.automaticallyAdjustsScrollViewInsets = NO;

Update for iOS 11

if #available(iOS 11.0, *) {
    scrollView.contentInsetAdjustmentBehavior = .never
} else {
    automaticallyAdjustsScrollViewInsets = false
}

Inspector: Select scrollView and set up Content Insets - never