I think every manufacturer re-defines "the market" until whatever they sell comes out with the largest share. So you'll get one who claims to be the largest "automation" supplier, or the largest "control systems" supplier, or the largest "PLC" supplier etc. Then you have the tricky task of getting Allen Bradley to define for you exactly what it is they have 51% of. And even if they did divulge their definition, would you necessarily agree with it? What about our own dearly beloved Smoke and Mirrors Inc. headquartered right here at this site? [See other posts to numerous to mention] Why, we must have 101% (at least) of the market share for something.
These market share figues are probably for pumping up the shareholders (annual reports etc), pumping up the company's own sales staff, and not much else. We probably all know who the big players in the business are, and whether it's 51% or 49% who cares?
Regards
Ken