EXC Bad Instruction
<p>In was wondering why I keep getting this error message, EXC Bad Instruction could someone help me out and tell me why.</p>

<p>Here is the code.</p>

<pre><code> func updateStocks() {
    let stockManager:StockManagerSingleton = StockManagerSingleton.sharedInstance
    stockManager.updateListOfSymbols(stocks)

    //Repeat this method after 15 secs. (For simplicity of the tutorial we are not cancelling it never)
    dispatch_after(
        dispatch_time(
            DISPATCH_TIME_NOW,
            Int64(15 * Double(NSEC_PER_SEC))
        ),
        dispatch_get_main_queue(),
        {
            self.updateStocks()
        }
    )
}

//4
func stocksUpdated(notification: NSNotification) {
    let values = (notification.userInfo as! Dictionary&lt;String,NSArray&gt;)
    let stocksReceived:NSArray = values[kNotificationStocksUpdated]!
    stocks.removeAll(keepCapacity: false)
    for quote in stocksReceived {
        let quoteDict:NSDictionary = quote as! NSDictionary
        let changeInPercentString = quoteDict["ChangeInPercent"] as! String
        let changeInPercentStringClean: NSString = (changeInPercentString as NSString).substringToIndex((changeInPercentString as NSString).length-1)
        stocks.append(quoteDict["symbol"] as! String,changeInPercentStringClean.doubleValue)
    }
    tableView.reloadData()
    NSLog("Symbols Values updated :)")
}
}
</code></pre>

<p>The line with the error in it is, </p>

<pre><code>let changeInPercentString = quoteDict["ChangeInPercent"] as! String
</code></pre>