I would argue that Google and Motorola never "merged".

Google just bought out the patents of Motorola and dumped the company away to Lenovo afterwards. There was no merging, no redundant employee elimination process, like in other mergers.

Plus, this number is obviously a large outlier. An actual stats person would just go calculate the figures with the outlier removed- Cisco probably made much larger acquisitions, employee count-wise, than Google in that case.