good question,
i have heard up to 50% same content was allowed,
also heard being penalized for having the same footer or disclaimer on every page (boilerplate)
i realy do not think the code or template is being considerated as content and looked at it this way
people even complain the links in their left- or uppermenu wich do apear on every page,part of the template, are not seen or counted by the searchengines
my 2 cents