.7% ( 201428.7 % )", "29.6% ( 29.6 % )", "29.6% ( 29.6 % ) 201477.8% ( 201477.8 % )"], ["weighted average expected volatility of underlying stock price", "28.2% ( 28.2 % )", "29.6% ( 29.6 % )", "54.30% ( 54.30 % )"], ["expected annual dividends", "n/a", "n/a", "n/a"]]