Accountants Can't Count

Every day, on my way into work, I see a giant poster on the tube wall advertising the Institute of Charted Accountants, which reads thus:

"Over 84% of FTSE 100 companies have an ACA on their board."

- also available on their site. Now, whilst this may well be true, it seems an odd way to phrase things. There are, by definition, one hundred FTSE100 companies. As such, it surely shouldn't be too hard to come out with an exact percentage.

I was tempted to believe that maybe this was just some clever marketer trying to make it seem like there were possible many more than just 85 FTSE100 companies with an ACA on their board. But, frankly, having seen the rest of the advert (a picture of a fairly shoddy leather chair), I don't really believe they hired a marketing consultant. I'm more inclined to believe it's just a rounding error..