Not all goals are goalkeeper error. I don't know why you are trying to use statistics to prove that Howard is ok rather than what you see on a saturday.
Shot on goal statistics can be massively misleading as they don't account for distance, power or accuracy of the shot. The only way to properly judge a keeper is by how many above average saves he makes compared to how many goals he costs. Howard is massively in the negative.
But in order for that to be true, we would have to be giving up an unusually high number of shots on target that are weak and go right at him. That isn't the case in my observation, and I can't think of any earthly reason it would be the case. Don't you think it's more likely that a lot of Everton supporters have an axe to grind with Howard after his admittedly terrible performances last season, and so are only seeing the negatives now?
Again, I doubt anyone here has been able to watch every Premier League match played by every club, so the only way to actually compare Howard to the rest of the keepers in the league is by looking at the overall numbers and trying to find the pattern in them. There isn't any way to twist those numbers to make Howard anything worse than an average keeper overall this season. If anyone on this forum has actually been able to watch all 170 Premier League matches that have been played this season (or even a majority of them) and could say that Howard is truly that bad relative to all of the other keepers, then I will shut up about it. Until then, stop telling me to judge him based purely on what you see, because you haven't seen everyone else.