Gw2 client DL percentage should based on size
The percentage is based on the amount of data being downloaded during that section. Per example, if you close the launcher when the download is at 15%, when you run it again it will restart the download from where it left, but the status will start at 0% again but this percentage is based on how much data is left, not account what was already downloaded.
The percentage is based on number of files downloaded per download session. Not on data.
This issue has been discussed on the forums many times; perhaps, there is a technical reason why the percentage works this way, and has not been changed since launch.
Good luck.
%-based download meters tend to be misleading in other ways. In the end, what most people really want to know is: how much time remains before the DL completes and there aren’t any reliable ways to measure that, since there are all sorts of variables that affect that.
The distributor can reliably count the number of files and so that’s why some publishers go with that, instead of how many megs to go.