In 14.5hrs you used 91% and GSam is showing 7% per hour. I'd say that's actually pretty good. Keep in mind also that those percentages shown are relative to the total amount used, not the total of your battery. Example: If you have 60% of your battery remaining that would mean that 40% has been used. So if it shows that Android System used 25% then it means that it used 25% of the 40% used or 10% (25% of 40%) of your total battery.