In that case, you should divide by "expected", so you get a percentage difference for each day. (Normalizing by total for the year doesn't make sense, since imagine that there were 300 days per month instead of 30 - your numbers would be divided by 10 again, but the data you want to visualize would stay the same.)
I made an update using standard deviation and Z-score charts instead of my homebrew normalization function (see "Update"): http://robert.io/posts/4.html
