Redmine

Currently not possible. The options are hardcoded into the Issue form.

Seems you would have to write a plugin for that yourself. (A simple Javascript script that replaces the options of the issue edit form select box should do the trick)

Perhaps this is what you are looking for in the mean time...
https://github.com/guilhermenoronha/redmine_percent_done_configuration

OT but nevertheless:

Bernhard Rohloff wrote:

Perhaps this is what you are looking for in the mean time...
https://github.com/guilhermenoronha/redmine_percent_done_configuration

I don't think so. This plugin overrides /app/views/issues/_attributes.html.erb with a version that is last updated on the 30th of October 2013. That most likely won't work at all or at least give a bunch of other problems with more recent Redmine releases.

Make sure you know what plugins you decide to use and always check their sources.

+1 IMPORTANT!
I currently have the same problem!