That shouldn't matter much if the rate of failure is measured as is the case with that graph. You're looking at the number of failures per 100 units after 2 and 3 years. The chart makes who ships how many unimportant.
You're referring to ratios, yeah that's very true. It may SEEM like Acer has a higher failure rate because I keep fixing the damn things, but that only means there's more of them.