The current bull market in stocks is only halfway through its potential, according to a new report from Ned Davis Research (NDR). What Happened: The current bull market, which has lasted for 344 trading days, could continue for the foreseeable future, as per a Wednesday note from NDR, reported by Business Insider. On average, bull markets last for 694 trading days, suggesting that the current rally is only at the halfway mark. NDR created a sentiment chart that measures the time the S&P 500 goes without a 20% decline, the most commonly cited threshold for stocks to be considered in a bear mark…