Mikeg's spreadsheet shows the distribution of IB's across the year in the same statistical bell curve that we are used to from Market Profile (except its orientation is horizontal which is the traditional orientation for a bell curve).
Very interesting results and what you would expect with a concentration around the median and then tailing off on either side.
ER2 shows the most even distribution but that is also because of the nature of the data. Points are being used when compared to YM (for example) where ticks are being used. (In YM points and ticks are the same but in ER2 they are not.)